83A - Magical Array - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
long long s2(int n){return (1LL*n*(n+1))/2;}
void run_case(){
    int n;
    scanf("%d",&n);
    vector<int>a(n);
    for(int &x: a)scanf("%d",&x);
    long long ret=0;
    for(int i,j=0;j<n;){
        for(i=j;j<n && a[i]==a[j];++j);
        ret += s2(j-i);
    }
    printf("%lld\n",ret);
}
int main(){
    int tc=1;
    for(;tc--;)run_case();
}