为什么 编译 不了啊

#include<bits/stdc++.h>
#define int long long

using namespace std;
struct node {
	int w, s, v;
} a[10000005];
int dp[10000005];

bool cmp(node a,node b) {
	return a.w + a.s < b.w + b.s;
}

int read() {
	int x = 0,t = 1;
	char ch = getchar();
	while (ch < '0' || ch > '9') {
		if (ch == '-')
			t -= 1;
		ch = getchar();
	}
	
	while (ch >= '0' && ch <= '9') {
		x = x * 10 + ch - '0';
		ch = getchar();
	} 
	
	return x * t;
}

void write(int x) {
	if (x < 0) {
		putchar('-');
		x = -x;
	} 
	
	if (x > 9) {
		write(x / 10);
	}
	
	putchar(x % 10 + '0');
}

signed main() {
	freopen("chair.in", "r", stdin);
	freopen("chair.out", "w", stdout);
	
	int T;
	T = read();
	while (T --) {
		memset(dp, 0, sizeof(dp));
		int n, ans = 0;
		n = read();
		for (int i = 1;i <= n;i ++)
			a[i].w = read(), a[i].s = read(), a[i].v = a[i].w;
		
		sort(a + 1, a + n + 1, cmp);
		dp[0] = 0;
		for (int i = 1;i <= n;i ++) {
			for (int j = a[i].s;j >= 0;j --)
				dp[j + a[i].w] = max(dp[j + a[i].w], dp[j] + a[i].v);
		} 
		
		for (int i = 1;i <= 10000000;i ++)
			ans = max(ans, dp[i]);

		write(ans);
		putchar('\n');
	}
	
	return 0;
}