Submission #1039879

#	Time	Username	Problem	Language	Result	Execution time	Memory
1039879		sleepntsheep	Inside information (BOI21_servers)	C11	0 / 100	3568 ms	9320 KiB

servers

#include <stdio.h>
#include <stdlib.h>

#define N 120001

int n, q, pp[N], jj[N], dd[N], up[N], temp, inc[N];

int *eh[N], *fh[N], eo[N];

void pus_(int **eh, int *eo, int i, int j) {
    int o = eo[i]++;
    if (0 == o) eh[i] = (int*)malloc(2 * sizeof **eh);
    else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
    eh[i][o] = j;
}

void link(int u, int v, int w) {
    pus_(eh, eo, u, v);
    --eo[u];
    pus_(fh, eo, u, v);
    pus_(eh, eo, v, u);
    --eo[v];
    pus_(fh, eo, v, u);
}

void dfs(int u, int p) {
    dd[u] = dd[pp[u] = p] + 1;
    inc[u] = (up[u] > up[p]) + inc[p];
    for (int j = 0; j < eo[u]; ++j) if (eh[u][j] != p) {
        up[eh[u][j]] = fh[u][j];
        dfs(eh[u][j], u);
    }
}

int lca(int u, int v) {
    while (dd[u] != dd[v]) {
        if (dd[u] < dd[v]) temp = u, u = v, v = temp;
        u = (dd[jj[u]] >= dd[v]) ? jj[u] : pp[u];
    }
    while (u != v)
        if (jj[u] != jj[v]) u = jj[u], v = jj[v];
        else u = pp[u], v = pp[v];
    return u;
}

int anc(int u, int dep) {
    while (dd[u] > dep)
        if (dd[jj[u]] >= dep) u = jj[u];
        else u = pp[u];
    return u;
}


struct Query {
    char type;
    int a, b;
    int ans;
} qq[N];

/* v = data node, u = ask node */
int query_yesno(int u, int v) {
    if (u == v) return 1;
    int a = lca(u, v);
    int va = anc(v, dd[a] + 1);
    int ua = anc(u, dd[a] + 1);

    if (u == a)
        return inc[v] - inc[va] == dd[u] - dd[a] - 1;
    if (v == a)
        return inc[u] - inc[ua] == 0;

    return (dd[u] - dd[a] + 1 == inc[v] - inc[va]) && (0 == inc[u] - inc[ua])
        && up[va] < up[ua];
}

int main() {
    scanf("%d%d", &n, &q);

    q = n + q - 1;
    for (int j = 0, i = 0; i < q; ++i) {
        char c;
        int a, b;
        scanf(" %c%d", &c, &a);
        if (c == 'S') {
            scanf("%d", &b);
            link(a, b, j++);
        } else if (c == 'Q') {
            scanf("%d", &b);
        } else {
        }

        qq[i] = (struct Query){c, a, b};
    }

    jj[1] = 1;
    dfs(1, 1);

    for (int i = 0; i < q; ++i) {
        if (qq[i].type == 'Q') {
            puts(query_yesno(qq[i].a, qq[i].b) ? "YES": "NO");
        }
    }
}

Compilation message (stderr)

servers.c: In function 'pus_':
servers.c:13:26: warning: suggest parentheses around '-' in operand of '&' [-Wparentheses]
   13 |     else if (0 == (o & o - 1)) eh[i] = (int*)realloc(eh[i], 2 * o * sizeof **eh);
      |                        ~~^~~
servers.c: In function 'main':
servers.c:77:5: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |     scanf("%d%d", &n, &q);
      |     ^~~~~~~~~~~~~~~~~~~~~
servers.c:83:9: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |         scanf(" %c%d", &c, &a);
      |         ^~~~~~~~~~~~~~~~~~~~~~
servers.c:85:13: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   85 |             scanf("%d", &b);
      |             ^~~~~~~~~~~~~~~
servers.c:88:13: warning: ignoring return value of 'scanf' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |             scanf("%d", &b);
      |             ^~~~~~~~~~~~~~~

• Subtask 1: 0 / 2.5
• Subtask 2: 0 / 2.5
• Subtask 3: 0 / 2.5
• Subtask 4: 0 / 2.5
• Subtask 5: 0 / 5
• Subtask 6: 0 / 5
• Subtask 7: 0 / 10
• Subtask 8: 0 / 10
• Subtask 9: 0 / 12.5
• Subtask 10: 0 / 12.5
• Subtask 11: 0 / 17.5
• Subtask 12: 0 / 17.5