diff --git a/answering.md b/answering.md
new file mode 100644
index 0000000..68f2995
--- /dev/null
+++ b/answering.md
@@ -0,0 +1,7 @@
+answer code goes as follows
+
+EASY PROBLEM 7
+
+ANSWER CODE : E07.cpp OR E07.py etc
+
+similarly M for medium and H for hard
\ No newline at end of file
diff --git a/answers/E01.cpp b/answers/E01.cpp
new file mode 100644
index 0000000..5650c8a
--- /dev/null
+++ b/answers/E01.cpp
@@ -0,0 +1,17 @@
+  
+#include<iostream>
+//dont forget the case of a=0;
+using namespace std;
+long long int sol(long long int a){
+	if (a==0)return 0;
+	if(a%2==1)return 1;
+	else return 2*sol(a/2);
+}
+int main(){
+	long long int a;
+	while(!feof(stdin)){
+		cin>>a;
+		cout<<sol(a)<<endl;
+	}
+	return 0;
+}
\ No newline at end of file
diff --git a/answers/E02.cpp b/answers/E02.cpp
new file mode 100644
index 0000000..a34498a
--- /dev/null
+++ b/answers/E02.cpp
@@ -0,0 +1,25 @@
+#include<iostream>
+#include<cmath>
+using namespace std;
+int i;
+#define geti(x) int x;cin>>x;
+#define getl(x) long long int x;in>>x;
+#define FOR(i,a,b) for(i=a;i<b;i++)
+int run(){
+	geti(n)
+	int a[24][60]={0};
+	int h,m,maximum=0;
+	FOR(i,0,n-1){
+		cin>>h>>m;
+		a[h][m]++;
+		maximum=max(maximum,a[h][m]);
+	}
+	cout<<maximum<<endl;
+	return 0;
+}
+int main(){
+	geti(t)
+	while(t--)
+		run();
+	return 0;
+}
diff --git a/answers/E03_GSS1.cpp b/answers/E03_GSS1.cpp
new file mode 100644
index 0000000..e99ff23
--- /dev/null
+++ b/answers/E03_GSS1.cpp
@@ -0,0 +1,87 @@
+#include<bits/stdc++.h>
+using namespace std;
+typedef long long int ll;
+class tree{
+    public:
+        ll sum;
+        ll maxSum;
+        ll maxPrefixSum;
+        ll maxSuffixSum;
+}segTree[200005];
+int a[50004],n;
+tree zero;
+tree join(tree left,tree right){
+    tree sol;
+    sol.sum=left.sum+right.sum;
+    sol.maxSum=max(left.maxSum,right.maxSum);
+    if(left.maxSum>=0&&right.maxSum>=0)
+    sol.maxSum=max(sol.maxSum,left.maxSuffixSum+right.maxPrefixSum);
+    sol.maxPrefixSum=max(left.maxPrefixSum,left.sum+right.maxPrefixSum);
+    sol.maxSuffixSum=max(right.maxSuffixSum,right.sum+left.maxSuffixSum);
+    return sol;
+}
+void buildSegTree(int i,int l,int r){
+    if(l>r)return ;
+    if(l==r){
+        segTree[i].sum=a[l];
+        segTree[i].maxSum=a[l];
+        segTree[i].maxPrefixSum=a[l];
+        segTree[i].maxSuffixSum=a[l];
+    }
+    else{
+        int mid=(l+r)/2;
+        buildSegTree(2*i,l,mid);
+        buildSegTree(2*i+1,mid+1,r);
+        segTree[i]=join(segTree[2*i],segTree[2*i+1]);
+    }
+}
+tree query_old(int treeIndex,int treeLeft,int treeRight,int l,int r){
+    if(treeLeft>treeRight)return zero;
+    if(treeLeft==treeRight)return segTree[treeIndex];
+    int treeMid=(treeLeft+treeRight)/2;
+    if(treeMid<l)return query_old(2*treeIndex+1,treeMid+1,treeRight,l,r);
+    if(treeMid>=r)return query_old(2*treeIndex,treeLeft,treeMid,l,r);
+    return join(query_old(2*treeIndex,treeLeft,treeMid,l,r),query_old(2*treeIndex+1,treeMid+1,treeRight,l,r));
+}
+
+tree query_new(int node,int start,int end,int l,int r)
+{
+    if(r<start || l>end)
+    {
+        tree zero;
+          zero.sum=-20000;
+zero.maxSum=-20000;
+zero.maxPrefixSum=-20000;
+zero.maxSuffixSum=-20000;
+    return zero;
+    }
+    if(start>=l && end<=r)
+    {
+        return segTree[node];
+    }
+    int mid=(start+end)/2;
+    tree p1=query_new(2*node,start,mid,l,r);
+    tree p2=query_new(2*node+1,mid+1,end,l,r);
+    tree temp=join(p1,p2);
+    return temp;
+}
+int main(){
+    
+	ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    zero.maxPrefixSum=zero.maxSuffixSum=zero.sum=-20000;
+    zero.maxSum=-20000;
+    cin>>n;
+    for(int i=0;i<n;i++){
+        cin>>a[i];
+    }
+    buildSegTree(1,0,n-1);
+    int q;
+    cin>>q;
+    int l,r;
+    while(q--){
+        cin>>l>>r;
+        cout<<query_new(1,0,n-1,l-1,r-1).maxSum<<endl;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/answers/E04.cpp b/answers/E04.cpp
new file mode 100644
index 0000000..73713bc
--- /dev/null
+++ b/answers/E04.cpp
@@ -0,0 +1,21 @@
+#include<iostream>
+#include<cmath>
+using namespace std;
+#define geti(x) int x;cin>>x;
+#define getl(x) long long int x;in>>x;
+#define FOR(i,a,b) for(i=a;i<b;i++)
+long long int N;
+int run(){
+	cin>>N;
+	double sol2=(sqrt(1+8*N)-1)/2;
+	long long int sol=sol2;
+	if(sol+0.0!=sol2)sol+=1;
+	cout<<sol<<endl;
+	return 0;
+}
+int main(){
+	geti(t)
+	while(t--)
+		run();
+	return 0;
+}
diff --git a/answers/E05.txt b/answers/E05.txt
new file mode 100644
index 0000000..a67620c
--- /dev/null
+++ b/answers/E05.txt
@@ -0,0 +1 @@
+problem unvailable
\ No newline at end of file
diff --git a/answers/E06.txt b/answers/E06.txt
new file mode 100644
index 0000000..2d2dd09
--- /dev/null
+++ b/answers/E06.txt
@@ -0,0 +1 @@
+refer E04.cpp
\ No newline at end of file
diff --git a/answers/E07.cpp b/answers/E07.cpp
new file mode 100644
index 0000000..504bbac
--- /dev/null
+++ b/answers/E07.cpp
@@ -0,0 +1,101 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+vector<string> split_string(string);
+
+// Complete the twoArrays function below.
+string twoArrays(int k, vector<int> A, vector<int> B) {
+    sort(A.begin(),A.end());
+    sort(B.begin(),B.end(),greater<int>());
+    int l=A.size();
+    while(l--){
+        if(A[l]+B[l]<k)return "NO";
+    }
+
+
+    return "YES";
+}
+
+int main()
+{
+    ofstream fout(getenv("OUTPUT_PATH"));
+
+    int q;
+    cin >> q;
+    cin.ignore(numeric_limits<streamsize>::max(), '\n');
+
+    for (int q_itr = 0; q_itr < q; q_itr++) {
+        string nk_temp;
+        getline(cin, nk_temp);
+
+        vector<string> nk = split_string(nk_temp);
+
+        int n = stoi(nk[0]);
+
+        int k = stoi(nk[1]);
+
+        string A_temp_temp;
+        getline(cin, A_temp_temp);
+
+        vector<string> A_temp = split_string(A_temp_temp);
+
+        vector<int> A(n);
+
+        for (int i = 0; i < n; i++) {
+            int A_item = stoi(A_temp[i]);
+
+            A[i] = A_item;
+        }
+
+        string B_temp_temp;
+        getline(cin, B_temp_temp);
+
+        vector<string> B_temp = split_string(B_temp_temp);
+
+        vector<int> B(n);
+
+        for (int i = 0; i < n; i++) {
+            int B_item = stoi(B_temp[i]);
+
+            B[i] = B_item;
+        }
+
+        string result = twoArrays(k, A, B);
+
+        fout << result << "\n";
+    }
+
+    fout.close();
+
+    return 0;
+}
+
+vector<string> split_string(string input_string) {
+    string::iterator new_end = unique(input_string.begin(), input_string.end(), [] (const char &x, const char &y) {
+        return x == y and x == ' ';
+    });
+
+    input_string.erase(new_end, input_string.end());
+
+    while (input_string[input_string.length() - 1] == ' ') {
+        input_string.pop_back();
+    }
+
+    vector<string> splits;
+    char delimiter = ' ';
+
+    size_t i = 0;
+    size_t pos = input_string.find(delimiter);
+
+    while (pos != string::npos) {
+        splits.push_back(input_string.substr(i, pos - i));
+
+        i = pos + 1;
+        pos = input_string.find(delimiter, i);
+    }
+
+    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));
+
+    return splits;
+}
diff --git a/answers/E08_FREQUENT.cpp b/answers/E08_FREQUENT.cpp
new file mode 100644
index 0000000..3c371fe
--- /dev/null
+++ b/answers/E08_FREQUENT.cpp
@@ -0,0 +1,93 @@
+#include<bits/stdc++.h>
+using namespace std;
+typedef int ll;
+class tree{
+    public:
+        ll maxFrequency;
+        ll leftFrequency;
+        ll rightFrequency;
+        ll rightElement;
+        ll leftElement;
+};
+tree *segTree;
+int a[100004],n;
+tree zero;
+tree join(tree left,tree right){
+    tree sol;
+    sol.maxFrequency=max(left.maxFrequency,right.maxFrequency);
+    if(left.rightElement==right.leftElement)
+    sol.maxFrequency=max(sol.maxFrequency,left.rightFrequency+right.leftFrequency);
+    sol.leftFrequency=left.leftElement==right.leftElement?left.leftFrequency+right.leftFrequency:left.leftFrequency;
+    sol.rightFrequency=left.rightElement==right.rightElement?left.rightFrequency+right.rightFrequency:right.rightFrequency;
+    sol.leftElement=left.leftElement;
+    sol.rightElement=right.rightElement;
+    return sol;
+}
+void buildSegTree(int i,int l,int r){
+    if(l>r)return ;
+    if(l==r){
+        segTree[i].rightElement=a[l];
+        segTree[i].leftElement=a[l];
+        segTree[i].maxFrequency=1;
+        segTree[i].leftFrequency=segTree[i].rightFrequency=1;
+    }
+    else{
+        int mid=(l+r)/2;
+        buildSegTree(2*i,l,mid);
+        buildSegTree(2*i+1,mid+1,r);
+        segTree[i]=join(segTree[2*i],segTree[2*i+1]);
+    }
+}
+tree query_old(int treeIndex,int treeLeft,int treeRight,int l,int r){
+    if(treeLeft>treeRight)return zero;
+    if(treeLeft==treeRight)return segTree[treeIndex];
+    int treeMid=(treeLeft+treeRight)/2;
+    if(treeMid<l)return query_old(2*treeIndex+1,treeMid+1,treeRight,l,r);
+    if(treeMid>=r)return query_old(2*treeIndex,treeLeft,treeMid,l,r);
+    return join(query_old(2*treeIndex,treeLeft,treeMid,l,r),query_old(2*treeIndex+1,treeMid+1,treeRight,l,r));
+}
+
+tree query_new(int node,int start,int end,int l,int r)
+{
+    if(r<start || l>end)
+    {
+        tree zero;
+        zero.rightElement=0;
+        zero.leftElement=0;
+        zero.maxFrequency=0;
+        zero.leftFrequency=zero.rightFrequency=0;
+        return zero;
+    }
+    if(start>=l && end<=r)
+    {
+        return segTree[node];
+    }
+    int mid=(start+end)/2;
+    tree p1=query_new(2*node,start,mid,l,r);
+    tree p2=query_new(2*node+1,mid+1,end,l,r);
+    tree temp=join(p1,p2);
+    return temp;
+}
+int main(){
+    
+	ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    int q;
+    cin>>n;
+    while(n){
+        tree myTree[4*n];
+        segTree=myTree;
+        cin>>q;
+        for(int i=0;i<n;i++){
+            cin>>a[i];
+        }
+        buildSegTree(1,0,n-1);
+        int l,r;
+        while(q--){
+            cin>>l>>r;
+            cout<<query_new(1,0,n-1,l-1,r-1).maxFrequency<<endl;
+        }
+        cin>>n;
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/answers/E09_BUGLIFE.cpp b/answers/E09_BUGLIFE.cpp
new file mode 100644
index 0000000..29b2ae9
--- /dev/null
+++ b/answers/E09_BUGLIFE.cpp
@@ -0,0 +1,51 @@
+#include<bits/stdc++.h>
+using namespace std;
+#define geti(x) int x;cin>>x;
+#define getl(x) long long int x;in>>x;
+#define FOR(i,a,b) for(i=a;i<b;i++)
+#define pb push_back
+bool dfs(vector <int> *v,int *color,int i){
+    for(int k:v[i]){
+        if(color[k]==0){
+            color[k]=-color[i];
+            if(dfs(v,color,k))return true;
+        }
+        if(color[k]==color[i]){
+            return true;
+        }
+    }
+    return false;
+}
+bool run(){
+	int i,t1,t2,n,q;
+    cin>>n>>q;
+    vector <int> v[n+1];
+    while(q--){
+        cin>>t1>>t2;
+        v[t1].pb(t2);
+        v[t2].pb(t1);
+    }
+    int color[n+1]={0};
+    for(i=1;i<=n;i++){
+        if(color[i]==0&&v[i].size()!=0){
+            color[i]=1;
+            if(dfs(v,color,i))return true;
+        }
+    }
+	return false;
+}
+int main(){
+	ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+	geti(t)
+    int i;
+	FOR(i,1,t+1){
+        cout<<"Scenario #"<<i<<":\n";
+        if(run())
+            cout<<"Suspicious bugs found!\n";
+		else
+            cout<<"No suspicious bugs found!\n";
+        
+    }
+	return 0;
+}
diff --git a/answers/E13_COINS.cpp b/answers/E13_COINS.cpp
new file mode 100644
index 0000000..f2d8cfb
--- /dev/null
+++ b/answers/E13_COINS.cpp
@@ -0,0 +1,24 @@
+#include<iostream>
+#include<map>
+using namespace std;
+class solution{
+	private:
+		map <int,long long int> m;
+	public:
+	long long int byteland_doller_conversion(int n){
+		if(n==0)return 0;
+		if (m[n]!=0)return m[n];
+		long long int answer=byteland_doller_conversion(n/2)+byteland_doller_conversion(n/3)+byteland_doller_conversion(n/4);
+		if(answer<n)answer=n;
+		m[n]=answer;
+		return answer;
+	}
+};
+int main(){
+	solution s;
+	long long int n;
+	while(cin>>n){
+		cout<<s.byteland_doller_conversion(n)<<endl;
+	}
+	return 0;
+}
diff --git a/answers/E19_HORRIBLE.cpp b/answers/E19_HORRIBLE.cpp
new file mode 100644
index 0000000..cdc8b2b
--- /dev/null
+++ b/answers/E19_HORRIBLE.cpp
@@ -0,0 +1,88 @@
+#include<iostream>
+using namespace std;
+typedef long long ll;
+class node{
+public:
+    long long int sum;
+    long long int extra;
+    node *left=NULL;
+    node *right=NULL;
+    node(ll sum=0,ll extra=0){
+        this->sum=sum;
+        this->extra=extra;
+    }
+    void destroy(){
+        if(left!=NULL){
+            left->destroy();
+            free(left);
+        }
+        if(right!=NULL){
+            right->destroy();
+            free(right);
+        }
+    }
+    ~node(){
+        destroy();
+    }
+    void createChildren(){
+        if(left==NULL)left=(node *)malloc(sizeof(node));
+        if(right==NULL)right=(node *)malloc(sizeof(node));
+    }
+    void propagateExtra(ll start,ll end){
+        if(start==end)return;
+        ll mid=(start+end)/2;
+        left->extra+=extra;
+        left->sum+=extra*(mid-start+1);
+        right->extra+=extra;
+        right->sum+=extra*(end-mid-1+1);
+        extra=0;
+    }
+    void update(ll start,ll end,ll l,ll r,ll value){
+        if(l>end||r<start)
+            return;
+        if(l<=start&&end<=r){
+            if(start!=end)
+                extra+=value;
+            sum+=(end-start+1)*value;
+            return;
+        }
+        ll mid=(start+end)/2;
+        createChildren();
+        if(extra)propagateExtra(start,end);
+        left->update(start,mid,l,r,value);
+        right->update(mid+1,end,l,r,value);
+        sum=right->sum+left->sum;
+    }
+    long long int query(ll start,ll end,ll l,ll r){
+        if(l>end||r<start)return 0;
+        if(l<=start&&end<=r)return sum;
+        int mid=(start+end)/2;
+        createChildren();
+        if(extra)propagateExtra(start,end);
+        return left->query(start,mid,l,r)+right->query(mid+1,end,l,r);
+    }
+};
+void run(node &head){
+    int n,c;
+    cin>>n>>c;
+    ll type,l,r,value;
+    while(c--){
+        cin>>type>>l>>r;
+        if(!type){
+            cin>>value;
+            head.update(1,n,l,r,value);
+        }
+        else{
+            cout<<head.query(1,n,l,r)<<"\n";
+        }
+
+    }
+}
+int main(){
+    ll t;
+    cin>>t;
+    node head[t];
+    while(t--){
+        run(head[t]);
+    }
+}
\ No newline at end of file
diff --git a/answers/M52_GSS3.cpp b/answers/M52_GSS3.cpp
new file mode 100644
index 0000000..1a18f04
--- /dev/null
+++ b/answers/M52_GSS3.cpp
@@ -0,0 +1,97 @@
+#include<bits/stdc++.h>
+using namespace std;
+typedef long long int ll;
+class tree{
+    public:
+        ll sum;
+        ll maxSum;
+        ll maxPrefixSum;
+        ll maxSuffixSum;
+}segTree[200005];
+int a[50004],n;
+tree zero;
+tree join(tree left,tree right){
+    tree sol;
+    sol.sum=left.sum+right.sum;
+    sol.maxSum=max(left.maxSum,right.maxSum);
+    if(left.maxSum>=0&&right.maxSum>=0)
+    sol.maxSum=max(sol.maxSum,left.maxSuffixSum+right.maxPrefixSum);
+    sol.maxPrefixSum=max(left.maxPrefixSum,left.sum+right.maxPrefixSum);
+    sol.maxSuffixSum=max(right.maxSuffixSum,right.sum+left.maxSuffixSum);
+    return sol;
+}
+void buildSegTree(int i,int l,int r){
+    if(l>r)return ;
+    if(l==r){
+        segTree[i].sum=a[l];
+        segTree[i].maxSum=a[l];
+        segTree[i].maxPrefixSum=a[l];
+        segTree[i].maxSuffixSum=a[l];
+    }
+    else{
+        int mid=(l+r)/2;
+        buildSegTree(2*i,l,mid);
+        buildSegTree(2*i+1,mid+1,r);
+        segTree[i]=join(segTree[2*i],segTree[2*i+1]);
+    }
+}
+
+tree query(int node,int start,int end,int l,int r)
+{
+    if(r<start || l>end)
+    {
+        tree zero;
+          zero.sum=-20000;
+zero.maxSum=-20000;
+zero.maxPrefixSum=-20000;
+zero.maxSuffixSum=-20000;
+    return zero;
+    }
+    if(start>=l && end<=r)
+    {
+        return segTree[node];
+    }
+    int mid=(start+end)/2;
+    tree p1=query(2*node,start,mid,l,r);
+    tree p2=query(2*node+1,mid+1,end,l,r);
+    tree temp=join(p1,p2);
+    return temp;
+}
+void update(int node,int start,int end,int leaf,int value){
+    if(start==end){
+        segTree[node].sum=segTree[node].maxSum=segTree[node].maxPrefixSum=segTree[node].maxSuffixSum=value;
+        return;
+    }
+    int mid=(start+end)/2;
+    if(leaf<=mid){
+        update(node*2,start,mid,leaf,value);
+    }
+    else{
+        update(2*node+1,mid+1,end,leaf,value);
+    }
+    segTree[node]=join(segTree[2*node],segTree[2*node+1]);
+}
+int main(){
+    
+	ios_base::sync_with_stdio(false);
+    cin.tie(NULL);
+    zero.maxPrefixSum=zero.maxSuffixSum=zero.sum=-20000;
+    zero.maxSum=-20000;
+    cin>>n;
+    for(int i=0;i<n;i++){
+        cin>>a[i];
+    }
+    buildSegTree(1,0,n-1);
+    int q;
+    cin>>q;
+    int l,r;
+    int type;
+    while(q--){
+        cin>>type>>l>>r;
+        if(type)
+            cout<<query(1,0,n-1,l-1,r-1).maxSum<<endl;
+        else
+            update(1,0,n-1,l-1,r);
+    }
+    return 0;
+}
\ No newline at end of file
diff --git a/answers/input b/answers/input
new file mode 100644
index 0000000..92b215c
--- /dev/null
+++ b/answers/input
@@ -0,0 +1,15 @@
+2
+8 6
+0 2 4 26
+0 4 8 80
+0 4 5 20
+1 8 8
+0 5 7 14
+1 4 8
+8 6
+0 2 4 26
+0 4 8 80
+0 4 5 20
+1 8 8
+0 5 7 14
+1 4 8
\ No newline at end of file
diff --git a/readme.md b/readme.md
index b199f2f..8da9788 100644
--- a/readme.md
+++ b/readme.md
@@ -98,25 +98,25 @@ To mark the checkbox, change [ ] to [x].
 
 #### Easy
 
-1. [ ] [https://goo.gl/Kkf8eD](https://goo.gl/Kkf8eD)
-2. [ ] [https://www.codechef.com/problems/SCC0103](https://www.codechef.com/problems/SCC0103)
-3. [ ] [http://www.spoj.com/problems/GSS1/](http://www.spoj.com/problems/GSS1/)
-4. [ ] [https://www.codechef.com/problems/BITMASK3](https://www.codechef.com/problems/BITMASK3)
-5. [ ] [https://goo.gl/PTpmny](https://goo.gl/PTpmny)
-6. [ ] [https://www.codechef.com/problems/BITMASK3](https://www.codechef.com/problems/BITMASK3)
-7. [ ] [https://www.hackerrank.com/challenges/two-arrays/problem](https://www.hackerrank.com/challenges/two-arrays/problem)
-8. [ ] [http://www.spoj.com/problems/FREQUENT/](http://www.spoj.com/problems/FREQUENT/)
-9. [ ] [http://www.spoj.com/problems/BUGLIFE/](http://www.spoj.com/problems/BUGLIFE/)
-10. [ ] [https://goo.gl/shR8UK](https://goo.gl/shR8UK)
+1. [X] [https://goo.gl/Kkf8eD](https://goo.gl/Kkf8eD)
+2. [X] [https://www.codechef.com/problems/SCC0103](https://www.codechef.com/problems/SCC0103)
+3. [X] [http://www.spoj.com/problems/GSS1/](http://www.spoj.com/problems/GSS1/)
+4. [X] [https://www.codechef.com/problems/BITMASK3](https://www.codechef.com/problems/BITMASK3)
+5. [X] {not available}[https://goo.gl/PTpmny](https://goo.gl/PTpmny)
+6. [X] [https://www.codechef.com/problems/BITMASK3](https://www.codechef.com/problems/BITMASK3)
+7. [X] [https://www.hackerrank.com/challenges/two-arrays/problem](https://www.hackerrank.com/challenges/two-arrays/problem)
+8. [X] [http://www.spoj.com/problems/FREQUENT/](http://www.spoj.com/problems/FREQUENT/)
+9. [X] [http://www.spoj.com/problems/BUGLIFE/](http://www.spoj.com/problems/BUGLIFE/)
+10. [X] {not available}[https://goo.gl/shR8UK](https://goo.gl/shR8UK)
 11. [ ] [http://www.spoj.com/problems/GERGOVIA/](http://www.spoj.com/problems/GERGOVIA/)
 12. [ ] [http://codeforces.com/problemset/problem/793/C](http://codeforces.com/problemset/problem/793/C)
-13. [ ] [http://www.spoj.com/problems/COINS/](http://www.spoj.com/problems/COINS/)
+13. [X] [http://www.spoj.com/problems/COINS/](http://www.spoj.com/problems/COINS/)
 14. [ ] [https://goo.gl/h7a3mN](https://goo.gl/h7a3mN)
 15. [ ] [https://goo.gl/MDTg6s](https://goo.gl/MDTg6s)
 16. [ ] [http://www.spoj.com/problems/TOPOSORT/](http://www.spoj.com/problems/TOPOSORT/)
 17. [ ] [https://www.hackerrank.com/challenges/angry-children/problem](https://www.hackerrank.com/challenges/angry-children/problem)
 18. [ ] [http://www.spoj.com/problems/QUEEN/](http://www.spoj.com/problems/QUEEN/)
-19. [ ] [http://www.spoj.com/problems/HORRIBLE/](http://www.spoj.com/problems/HORRIBLE/)
+19. [X] [http://www.spoj.com/problems/HORRIBLE/](http://www.spoj.com/problems/HORRIBLE/)
 20. [ ] [http://www.spoj.com/problems/PAIRS1/](http://www.spoj.com/problems/PAIRS1/)
 21. [ ] [http://www.spoj.com/problems/JUSTAPAL/](http://www.spoj.com/problems/JUSTAPAL/)
 22. [ ] [https://goo.gl/m5DbXZ](https://goo.gl/m5DbXZ)
@@ -206,7 +206,7 @@ To mark the checkbox, change [ ] to [x].
 49. [ ] [http://codeforces.com/problemset/problem/596/D](http://codeforces.com/problemset/problem/596/D)
 50. [ ] [https://goo.gl/oXTucZ](https://goo.gl/oXTucZ)
 51. [ ] [http://www.spoj.com/problems/INVCNT/](http://www.spoj.com/problems/INVCNT/)
-52. [ ] [http://www.spoj.com/problems/GSS3/](http://www.spoj.com/problems/GSS3/)
+52. [X] [http://www.spoj.com/problems/GSS3/](http://www.spoj.com/problems/GSS3/)
 53. [ ] [http://codeforces.com/problemset/problem/340/D](http://codeforces.com/problemset/problem/340/D)
 54. [ ] [http://www.spoj.com/problems/RMID2/	[heaps]](http://www.spoj.com/problems/RMID2/)
 55. [ ] [http://www.spoj.com/problems/DCEPC206/](http://www.spoj.com/problems/DCEPC206/)
@@ -263,4 +263,5 @@ To mark the checkbox, change [ ] to [x].
 30. [ ] [https://goo.gl/nqXngJ](https://goo.gl/nqXngJ)
 31. [ ] [https://www.hackerrank.com/challenges/iterate-it/problem](https://www.hackerrank.com/challenges/iterate-it/problem)
 32. [ ] [https://www.codechef.com/problems/DGCD](https://www.codechef.com/problems/DGCD)
-33. [ ] [http://www.spoj.com/problems/ANARC05H/](http://www.spoj.com/problems/ANARC05H/)
\ No newline at end of file
+33. [ ] [http://www.spoj.com/problems/ANARC05H/](http://www.spoj.com/problems/ANARC05H/)
+