全 WA，bjd 哪里错了（几周前写的我都快忘了我的思路了 qaq）

#include <bits/stdc++.h>

using namespace std;

struct shelf {
	int h, t;
} book[100];

const int inf = 0x3f3f3f3f;

int dp[2][2186][2186];
int roll[100];

bool cmp (shelf x, shelf y) {
	return x.h > y.h;
}

int main () {
	int n;
	scanf("%d", &n);
	for (int i = 1; i <= n; i++)
		scanf("%d%d", &book[i].h, &book[i].t);
	sort(book + 1, book + n + 1, cmp);
	memset(dp, inf, sizeof(dp));
	dp[0][0][0] = dp[1][0][0] = 0;
	for (int i = 1; i <= n; i++)
		roll[i] = roll[i - 1] + book[i].t; 
	for (int i = 1; i <= n; i++) {
		memset(dp[i & 1], inf, sizeof(dp[i & 1]));
		for (int j = 0; j <= roll[i]; j++)
			for (int k = 0; k <= roll[i]; k++) {
				if (i != 0) 
					dp[i & 1][j + book[i].t][k] = min(dp[i & 1][j + book[i].t][k], dp[(i & 1) ^ 1][j][k]);
                else 
					dp[i & 1][j + book[i].t][k] = min(dp[i & 1][j + book[i].t][k], dp[(i & 1) ^ 1][j][k] + book[i].h);
                if (j != 0) 
					dp[i & 1][j][k + book[i].t] = min(dp[i & 1][j][k + book[i].t], dp[(i & 1) ^ 1][j][k]);
                else 
					dp[i & 1][j][k + book[i].t] = min(dp[i & 1][j][k + book[i].t], dp[(i & 1) ^ 1][j][k] + book[i].h);
                if (roll[i - 1] - j - k != 0) 
					dp[i & 1][j][k] = min(dp[i & 1][j][k], dp[(i & 1) ^ 1][j][k]);
                else 
					dp[i & 1][j][k] = min(dp[i & 1][j][k], dp[(i & 1) ^ 1][j][k] + book[i].h);
			}
	}
	long long ans = inf;
	for (int i = 1; i <= roll[n]; i++)
		for (int j = 1; j <= roll[n]; j++)
			if (roll[n] - i - j > 0)
				ans = min(ans, 1ll * max(roll[n] - i - j, max(i, j)) * (1ll * dp[n & 1][i][j]));
	printf("%lld", ans / (n - 1) * 10);
	return 0;
}