結果

問題 No.827 総神童数
ユーザー akakimidoriakakimidori
提出日時 2019-06-06 11:02:19
言語 C
(gcc 12.3.0)
結果
AC  
実行時間 91 ms / 2,000 ms
コード長 2,425 bytes
コンパイル時間 242 ms
コンパイル使用メモリ 31,872 KB
実行使用メモリ 7,296 KB
最終ジャッジ日時 2024-09-25 02:56:25
合計ジャッジ時間 4,387 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 1 ms
6,812 KB
testcase_01 AC 1 ms
6,940 KB
testcase_02 AC 1 ms
6,944 KB
testcase_03 AC 1 ms
6,944 KB
testcase_04 AC 1 ms
6,940 KB
testcase_05 AC 1 ms
6,944 KB
testcase_06 AC 1 ms
6,940 KB
testcase_07 AC 1 ms
6,944 KB
testcase_08 AC 1 ms
6,940 KB
testcase_09 AC 87 ms
7,296 KB
testcase_10 AC 29 ms
6,940 KB
testcase_11 AC 2 ms
6,944 KB
testcase_12 AC 13 ms
6,940 KB
testcase_13 AC 68 ms
6,944 KB
testcase_14 AC 3 ms
6,944 KB
testcase_15 AC 27 ms
6,940 KB
testcase_16 AC 68 ms
6,940 KB
testcase_17 AC 81 ms
7,040 KB
testcase_18 AC 35 ms
6,940 KB
testcase_19 AC 91 ms
7,168 KB
testcase_20 AC 66 ms
6,940 KB
testcase_21 AC 47 ms
6,940 KB
testcase_22 AC 72 ms
6,940 KB
testcase_23 AC 1 ms
6,944 KB
testcase_24 AC 81 ms
6,940 KB
testcase_25 AC 60 ms
6,940 KB
testcase_26 AC 81 ms
6,944 KB
testcase_27 AC 53 ms
6,940 KB
testcase_28 AC 52 ms
6,940 KB
testcase_29 AC 41 ms
6,944 KB
testcase_30 AC 13 ms
6,940 KB
testcase_31 AC 32 ms
6,944 KB
testcase_32 AC 31 ms
6,940 KB
testcase_33 AC 89 ms
7,040 KB
testcase_34 AC 81 ms
6,944 KB
testcase_35 AC 33 ms
6,944 KB
testcase_36 AC 46 ms
6,940 KB
testcase_37 AC 60 ms
6,940 KB
testcase_38 AC 87 ms
7,040 KB
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ソースコード

diff # 

#include<stdio.h>
#include<stdlib.h>
#include<stdint.h>
#include<inttypes.h>
#include<string.h>

typedef int32_t i32;
typedef int64_t i64;

typedef struct directed_edge {
  int32_t vertex;
  int32_t next;
} graph_edge;

typedef struct directedGraph {
  graph_edge *edge;
  int32_t *start;
  int32_t pointer;
  int32_t vertex_num;
  int32_t edge_max_size;
} graph;

graph* new_graph (const int vertex_num) {
  graph *g = (graph *) calloc (1, sizeof (graph));
  g->edge = (graph_edge *) calloc (1, sizeof (graph_edge));
  g->start = (int32_t *) calloc (vertex_num, sizeof (int32_t));
  g->pointer = 0;
  g->vertex_num = vertex_num;
  g->edge_max_size = 1;
  for (int32_t i = 0; i < vertex_num; ++i) {
    g->start[i] = -1;
  }
  return g;
}

void add_edge (graph *g, int32_t from, int32_t to) {
  if (g->pointer == g->edge_max_size) {
    g->edge_max_size *= 2;
    g->edge = (graph_edge *) realloc (g->edge, sizeof (graph_edge) * g->edge_max_size);
  }
  g->edge[g->pointer] = (graph_edge) {to, g->start[from]};
  g->start[from] = g->pointer++;
}

void BFS_graph (graph *g, int32_t src, i32 *d) {
  int32_t *q = (int32_t *) calloc (g->vertex_num, sizeof (int32_t));
  uint8_t *used = (uint8_t *) calloc (g->vertex_num, sizeof (uint8_t));
  int32_t front = 0;
  int32_t last = 0;
  used[src] = 1;
  q[last++] = src;
  while (front < last) {
    const int32_t v = q[front++];
    for (int32_t p = g->start[v]; p != -1; p = g->edge[p].next) {
      const int32_t u = g->edge[p].vertex;
      if (!used[u]) {
        used[u] = 1;
        q[last++] = u;
        d[u] = d[v] + 1;
      }
    }
  }
  free(q);
  free(used);
}

const i32 mod = 1000000007;

i32 mod_pow (i32 r, i32 n) {
  i32 t = 1;
  i32 s = r;
  while (n > 0) {
    if (n & 1) t = (i64) t * s % mod;
    s = (i64) s * s % mod;
    n >>= 1;
  }
  return t;
}

i32 inv (i32 a) {
  return mod_pow (a, mod - 2);
}

void run (void) {
  i32 n;
  scanf ("%" SCNi32, &n);
  graph *g = new_graph (n);
  for (i32 i = 1; i < n; ++i) {
    i32 a, b;
    scanf ("%" SCNi32 "%" SCNi32, &a, &b);
    a--; b--;
    add_edge (g, a, b);
    add_edge (g, b, a);
  }
  i32 *d = (i32 *) calloc (n, sizeof (i32));
  BFS_graph (g, 0, d);
  i32 ans = 0;
  for (i32 i = 0; i < n; ++i) {
    i32 x = d[i] + 1;
    ans = (ans + inv (x)) % mod;
  }
  for (i32 i = 1; i <= n; ++i) {
    ans = (i64) ans * i % mod;
  }
  printf ("%" PRIi32 "\n", ans);
}

int main (void) {
  run();
  return 0;
}
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