Problem YODANESS from SPOJ

YODANESS.cpp

@@ -0,0 +1,51 @@
+// Problem : YODANESS from SPOJ
+
+#include <bits/stdc++.h>
+using namespace std;
+
+void update(int BIT[], int v, int n){
+	for(;v<=n;v+=(v&(-v)))BIT[v]++;
+}
+
+int query(int BIT[], int v){
+	int ans = 0;
+	for(;v>0;v-=(v&(-v)))ans+=BIT[v];
+	return ans;
+}
+
+void solve(){
+	int n,i;
+	string s;
+	unordered_map<string,int> Hash;
+	cin>>n;
+	int a[n];
+
+	for(i=0;i<n;i++){
+		cin>>s;
+		Hash[s] = i+1;
+	}
+
+	for(i=0;i<n;i++){
+		cin>>s;
+		a[i] = Hash[s];
+	}
+
+	int BIT[n+1],res;
+	for(i=1;i<=n;i++)BIT[i] = 0;
+
+	res = 0;
+
+	for(i=0;i<n;i++){
+		res+=(a[i]-1-query(BIT,a[i]-1));
+		update(BIT,a[i],n);
+	}
+
+	cout<<res<<"\n";
+	return ;
+}
+
+int main(){
+	int t;
+	cin>>t;
+	while(t--)solve();
+}