POJ 3061 Subsequence

传送门

双指针

#include<iostream>
#include<algorithm>
#include<utility>
using namespace std;

typedef long long LL;
typedef pair<double, double> P;

const int maxn = 1e5 + 100;
const LL INF = 1e18;
const double eps = 1e-6;
const LL mod = 1e9 + 7;

int arr[maxn], sum[maxn];

void solve() {      
    int n, S; 
    cin >> n >> S;
    for(int i = 1; i <= n+5; i++) sum[i] = 0;

    for(int i = 1; i <= n; i++) {
        cin >> arr[i];
        sum[i] = sum[i-1] + arr[i];
    }
    int s = 0, t = 1;
    int res = n + 1;
    for(;;) {
        while(t <= n && sum[t] - sum[s] < S) {
            t++;
        }
        if(sum[t] - sum[s] < S) break;
        res = min(res, t - s);
        s++;
    }
    if(res == n + 1) cout << 0 << endl;
    else cout << res << endl;
}   

int main() {
    ios::sync_with_stdio(false);
    int t = 1; cin >> t;
    while(t--) {
        solve();
    }
    return 0;
}