感觉式子推的是对的啊，why 0pts?

#include <bits/stdc++.h>
using namespace std;

int n, m, a[2001][2001], f[2001][2001], ans = 1 << 30;

int main() {
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= m; j++)
			cin >> a[i][j];
	for (int i = 1; i <= n; i++) {
		for (int j = 1; j <= m; j++) {
			if (j == 1)
				f[i][j] = min(f[i - 1][j], f[i - 1][m]) + a[i][j];
			else
				f[i][j] = min(f[i - 1][j], f[i - 1][j - 1]) + a[i][j];
		}
	}
	for (int i = 1; i <= m; ++i)
		ans = min(ans, f[n][i]);
	cout << ans + 1;
	return 0;
}