백준_1806_부분합

✨문제: https://www.acmicpc.net/problem/1806

1806번: 부분합

 

✨알고리즘: 브루트포스-기타-투 포인터(Two Pointer)

 

✨중요 포인트: 문제조건이 '자연수'여서 이렇게 풀 수 있음.

 

✨코드:

#include <iostream>
#include <vector>
#include <climits>

using namespace std;

int main() {
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	int n, s;
	cin >> n >> s;
	vector<int> a(n);
	for (int i = 0; i < n; i++) {
		cin >> a[i];
	}
	int left = 0;
	int right = 0;
	int sum = a[0];
	int ans = INT_MAX;
	while (left <= right && right < n) {
		if (sum < s) {
			right++;
			sum += a[right];
		}
		else if (sum == s) {
			int cur = right - left + 1;
			if (cur < ans) ans = cur;
			right++;
			sum += a[right];
		}
		else if(sum > s) {
			int cur = right - left + 1;
			if (cur < ans) ans = cur;
			sum -= a[left];
			left++;
			if (left > right && left < n) {
				right = left;
				sum = a[left];
			}
		}
	}
	if (ans == INT_MAX) ans = 0;
	cout << ans << '\n';
	return 0;
}