#include <iostream>
#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
#include <algorithm>
using namespace std;
inline int read()
{
    int x = 0, f = 1;
    char ch = getchar();
    while (!isdigit(ch))
    {
        if (ch == '-')
            f = -f;
        ch = getchar();
    }
    while (isdigit(ch))
    {
        x = (x << 1) + (x << 3) + (ch ^ 48);
        ch = getchar();
    }
    return f * x;
}
#define N 110
#define M 10010
int n, m;
struct Edge
{
    int to, next, val;
} e[M];
int head[M];
int cnt;
inline void add(int from, int to, int val)
{
    e[++cnt].to = to;
    e[cnt].val = val;
    e[cnt].next = head[from];
    head[from] = cnt;
}
int c[N], u[N];
int in[N];
int is_out[N];
queue<int> q;
int vis[N];
int main()
{
    n = read(), m = read();
    for (int i = 1; i <= n; ++i)
    {
        c[i] = read(), u[i] = read();
        if (c[i] > 0)
            c[i] += u[i];
        is_out[i] = true;
    }
    int t1, t2, t3;
    for (int i = 1; i <= m; ++i)
    {
        t1 = read(), t2 = read(), t3 = read();
        add(t1, t2, t3);
        is_out[t1] = false;
        ++in[t2];
    }
    for (int i = 1; i <= n; ++i)
        if (!in[i])
        {
            q.push(i);
            vis[i] = true;
        }
    while (!q.empty())
    {
        int now = q.front();
        q.pop();
        c[now] -= u[now];
        if (c[now] > 0)
            for (int i = head[now]; i; i = e[i].next)
            {
                int to = e[i].to;
                c[to] += c[now] * e[i].val;
                in[to]--;
                if (!in[to] && !vis[to])
                {
                    q.push(to);
                    vis[to] = true;
                }
            }
    }
    int book = 0;
    for (int i = 1; i <= n; ++i)
        if (is_out[i] && c[i] > 0)
        {
            book = 1;
            printf("%d %d\n", i, c[i]);
        }
    if (!book)
    {
        printf("NULL\n");
    }
    return 0;
}

其中的

for (int i = 1; i <= n; ++i)
{
    c[i] = read(), u[i] = read();
    if (c[i] > 0)
        c[i] += u[i];
    is_out[i] = true;
}

c[i] > 0 我因样例先写成 c[i] == 1，仍可通过前四个测试点。