Create 1703F-YetAnotherProblemAboutPairsSatisfyingAnInequality.cpp

Author: DionysiosB

1703F-YetAnotherProblemAboutPairsSatisfyingAnInequality.cpp

@@ -0,0 +1,21 @@
+#include <cstdio>
+#include <vector>
+typedef long long ll;
+
+int main(){
+
+    ll t; scanf("%lld", &t);
+    while(t--){
+        ll n; scanf("%lld", &n);
+        std::vector<ll> v(n + 1, 0);
+        ll total(0);
+        for(ll p = 1; p <= n; p++){
+            ll x; scanf("%lld", &x);
+            v[p] = v[p - 1];
+            if(x < p){++v[p]; total += (x ? v[x - 1] : 0);}
+        }
+
+        printf("%lld\n", total);
+    }
+
+}