for(int i=1;i<=n;++i)
	for (int j=1;j <= n;++j) 		printf("%d%c", f[j],"\n "[j != n]);

这句话里的

"\n "[j!=n]

我真不懂。。。
我看的整个代码是这样的（其实就是这个的第 $17$ 题代码，结果在判断题第 $3$ 题丢分了呜呜~）：

#include <cstdio>
 
const int N = 5010;
const int M = 20010;
const int inf = 1073741823;

int e, bg[N], nx[M], to[M], wt[M];
inline void link(int u, int v, int w) {
    to[++e] = v;
    nx[e] = bg[u];
    wt[e] = w;
    bg[u] = e;
}

int n, m, u, v, w;
int f[N], h[N << 1];

void update(int x, int y) {
    x += n - 1;
    for (h[x] = y; x; x >>= 1)
        h[x >> 1] = f[h[x]] < f[h[x^1]] ? h[x] : h[x^1];
}

int main() {
    scanf("%d%d", &n, &m);
    for (int i = 0; i != m; ++i) {
        scanf("%d%d%d", &u, &v, &w);
        link(u, v, w);
    }
    int nn = n << 1;
    for (int i = 1; i <= n; ++i) {
        for (int j = 1; j != nn; ++j)
            h[j] = 0;
        for (int j = 0; j <= n; ++j)
            f[j] = inf;
        f[i] = 0;
        update(i, i);
        for (int j = i; true; j = h[1]) {
            if (f[j] == inf) break;
            for (int k = bg[j]; k; k = nx[k]) {
                if (f[j] + wt[k] < f[to[k]]) {
                    f[to[k]] = f[j] + wt[k];
                    update(to[k], to[k]);
                }
            }
            update(j, 0);
        }
        for (int j = 1; j <= n; ++j)
            printf("%d%c", f[j], "\n "[j != n]);
    }
    return 0;
}