Atcoder训练计划

#include<cstdio>
#include<iostream>
#define LL long long 
using namespace std;
main() {
     LL N, A, B;
     cin >> N >> A >> B;
     cout << max((LL)0, (N - 1) * B + A - (N - 1) * A - B + 1);
    return 0;
}

#include<cstdio>
#include<iostream>
#include<cstring>
#define LL long long 
using namespace std;
const int MAXN = 1e5 + 10;
char s[MAXN];
main() {
    scanf("%s", s + 1);
    int N = strlen(s + 1);
    LL ans = 0;
    for(int i = 1; i <= N; i++) {
        if(s[i] == 'U') ans += (N - i) + (i - 1) * 2;
        else ans += (N - i) * 2 + (i - 1);
    }
    cout << ans;
    return 0;
}