結果

問題 No.1612 I hate Construct a Palindrome
ユーザー 👑 ygussany
提出日時 2021-06-19 22:24:17
言語 C
(gcc 13.3.0)
結果
AC  
実行時間 78 ms / 2,000 ms
コード長 2,904 bytes
コンパイル時間 185 ms
コンパイル使用メモリ 32,560 KB
実行使用メモリ 11,776 KB
最終ジャッジ日時 2024-07-17 15:14:27
合計ジャッジ時間 3,168 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge2
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 36
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ソースコード

diff #
プレゼンテーションモードにする

#include <stdio.h>
typedef struct List {
    struct List *next;
    int v, id;
} list;
int is_palindrome(char S[])
{
    int i, j;
    for (j = 0; S[j] != 0; j++);
    for (i = 0, j--; i < j; i++, j--) if (S[i] != S[j]) break;
    if (i < j) return 0;
    else return 1;
}
int solve(int N, int M, list* adj[], list e[], char c[], int ans[])
{
    int i;
    list *p;
    for (i = 2; i <= M; i++) if (c[i] != c[1]) break;
    if (i > M) return -1;
    
    int u, w, x = adj[1]->v, par[2][100001][2], dist[2][100001] = {}, q[100001], head, tail;
    dist[0][x] = 1;
    q[0] = x;
    for (head = 0, tail = 1; head < tail; head++) {
        u = q[head];
        for (p = adj[u]; p != NULL; p = p->next) {
            w = p->v;
            if (dist[0][w] == 0) {
                dist[0][w] = dist[0][u] + 1;
                par[0][w][0] = u;
                par[0][w][1] = p->id;
                q[tail++] = w;
            }
        }
    }
    dist[1][N] = 1;
    q[0] = N;
    for (head = 0, tail = 1; head < tail; head++) {
        u = q[head];
        for (p = adj[u]; p != NULL; p = p->next) {
            w = p->v;
            if (dist[1][w] == 0) {
                dist[1][w] = dist[1][u] + 1;
                par[1][w][0] = u;
                par[1][w][1] = p->id;
                q[tail++] = w;
            }
        }
    }
    
    int j, k = 0, y, z;
    char S[200001];
    for (j = 1, i = adj[1]->id; j <= M; j++) if (c[j] != c[i]) break;
    y = e[(j-1)*2].v;
    z = e[j*2-1].v;
    ans[k] = i;
    S[k++] = c[i];
    if (dist[0][y] <= dist[0][z]) {
        k += dist[0][y] - 1;
        for (i = k - 1, u = y; u != x; i--, u = par[0][u][0]) {
            ans[i] = par[0][u][1];
            S[i] = c[ans[i]];
        }
        if (dist[1][y] < dist[1][z]) {
            ans[k] = j;
            S[k++] = c[j];
            ans[k] = j;
            S[k++] = c[j];
            for (u = y; u != N; k++, u = par[1][u][0]) {
                ans[k] = par[1][u][1];
                S[k] = c[ans[k]];
            }
        } else {
            ans[k] = j;
            S[k++] = c[j];
            for (u = z; u != N; k++, u = par[1][u][0]) {
                ans[k] = par[1][u][1];
                S[k] = c[ans[k]];
            }
        }
    } else {
        k += dist[0][z] - 1;
        for (i = k - 1, u = z; u != x; i--, u = par[0][u][0]) {
            ans[i] = par[0][u][1];
            S[i] = c[ans[i]];
        }
        
        if (dist[1][y] > dist[1][z]) {
            ans[k] = j;
            S[k++] = c[j];
            ans[k] = j;
            S[k++] = c[j];
            for (u = z; u != N; k++, u = par[1][u][0]) {
                ans[k] = par[1][u][1];
                S[k] = c[ans[k]];
            }
        } else {
            ans[k] = j;
            S[k++] = c[j];
            for (u = y; u != N; k++, u = par[1][u][0]) {
                ans[k] = par[1][u][1];
                S[k] = c[ans[k]];
            }
        }
    }
    
    if (is_palindrome(S) == 0) return k;
    else {
        ans[k] = ans[k-1];
        ans[k+1] = ans[k];
        return k + 2;
    }
}
int main()
{
    int i, N, M, u, w;
    char c[200001];
    list *adj[100001] = {}, e[400001];
    scanf("%d %d", &N, &M);
    for (i = 0; i < M; i++) {
        scanf("%d %d %c ", &u, &w, &(c[i+1]));
        e[i*2].v = w;
        e[i*2+1].v = u;
        e[i*2].id = i + 1;
        e[i*2+1].id = i + 1;
        e[i*2].next = adj[u];
        e[i*2+1].next = adj[w];
        adj[u] = &(e[i*2]);
        adj[w] = &(e[i*2+1]);
    }
    
    int ans[200001], k = solve(N, M, adj, e, c, ans);
    printf("%d\n", k);
    if (k >= 0) for (i = 0; i < k; i++) printf("%d\n", ans[i]);
    fflush(stdout);
    return 0;
}
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