Submission #101573

#	Time	Username	Problem	Language	Result	Execution time	Memory
101573		choikiwon	Sailing Race (CEOI12_race)	C++17	40 / 100	1833 ms	6272 KiB

race

#include<bits/stdc++.h>
using namespace std;

const int MN = 555;

int N, T;
int adj[MN][MN];

int cc1[MN][MN][2];
int dp1(int u, int v, int t) {
    int &ret = cc1[u][v][t];
    if(ret != -1) return ret;

    ret = 0;
    if(t) {
        for(int i = (u + 1) % N; i != v; i = (i + 1) % N) {
            if(adj[u][i]) {
                ret = max(ret, dp1(u, i, 0) + 1);
                ret = max(ret, dp1(i, v, 1) + 1);
            }
        }
    }
    else {
        for(int i = (u + 1) % N; i != v; i = (i + 1) % N) {
            if(adj[v][i]) {
                ret = max(ret, dp1(u, i, 0) + 1);
                ret = max(ret, dp1(i, v, 1) + 1);
            }
        }
    }
    return ret;
}

int cc2[MN][MN][2];
int dp2(int u, int v, int t) {
    int &ret = cc2[u][v][t];
    if(ret != -1) return ret;
    if(u == v) return ret = 0;

    ret = -1e9;
    if(t) {
        for(int i = (u + 1) % N;; i = (i + 1) % N) {
            if(adj[u][i]) {
                ret = max(ret, dp2(i, v, 1) + 1);
            }
            if(i == v) break;
        }
    }
    else {
        for(int i = (u + N - 1) % N;; i = (i + N - 1) % N) {
            if(adj[u][i]) {
                ret = max(ret, dp2(i, v, 0) + 1);
            }
            if(i == v) break;
        }
    }
    return ret;
}

int main() {
    scanf("%d %d", &N, &T);

    for(int i = 0; i < N; i++) {
        while(1) {
            int t; scanf("%d", &t);
            if(!t) break;
            t--;

            adj[i][t] = 1;
        }
    }

    memset(cc1, -1, sizeof(cc1));
    memset(cc2, -1, sizeof(cc2));

    int ans = 0;
    int p = 0;
    for(int i = 0; i < N; i++) {
        for(int j = 0; j < N; j++) if(i != j && adj[i][j]) {
            if(ans < dp1(i, j, 0) + 1) {
                ans = dp1(i, j, 0) + 1;
                p = i;
            }
            if(ans < dp1(j, i, 1) + 1) {
                ans = dp1(j, i, 1) + 1;
                p = i;
            }
        }
    }

    /*
    if(T) {
        for(int i = 0; i < N; i++) {
            vector<int> mx(N, -1e9);

            for(int j = (i + 1) % N; j != i; j = (j + 1) % N) {
                if(adj[i][j]) {
                    for(int k = (j + 1) % N; k != i; k = (k + 1) % N) {
                        if(ans < dp2(j, k, 1) + 2 + mx[k]) {
                            ans = dp2(j, k, 1) + 2 + mx[k];
                            p = i;
                        }
                    }
                }
                for(int k = (j + 1) % N; k != i; k = (k + 1) % N) {
                    if(adj[k][j]) {
                        mx[k] = max(mx[k], dp1(i, j, 0));
                    }
                }
            }

            mx = vector<int>(N, -1e9);
            for(int j = (i + N - 1) % N; j != i; j = (j + N - 1) % N) {
                if(adj[i][j]) {
                    for(int k = (j + N - 1) % N; k != i; k = (k + N - 1) % N) {
                        if(ans < dp2(j, k, 0) + 2 + mx[k]) {
                            ans = dp2(j, k, 0) + 2 + mx[k];
                            p = i;
                        }
                    }
                }
                for(int k = (j + N - 1) % N; k != i; k = (k + N - 1) % N) {
                    if(adj[k][j]) {
                        mx[k] = max(mx[k], dp1(j, i, 1));
                    }
                }
            }
        }

        for(int i = 0; i < N; i++) {
            vector<int> mx(N, -1e9);

            for(int j = (i + N - 1) % N; j != i; j = (j + N - 1) % N) {
                if(adj[j][i]) {
                    for(int k = (i + 1) % N; k != j; k = (k + 1) % N) {
                        if(ans < dp2(i, k, 1) + 2 + mx[k]) {
                            ans = dp2(i, k, 1) + 2 + mx[k];
                            p = j;
                        }
                    }
                }
                for(int k = (i + 1) % N; k != j; k = (k + 1) % N) {
                    if(adj[k][j]) {
                        mx[k] = max(mx[k], dp1(j, i, 1));
                    }
                }
            }

            mx = vector<int>(N, -1e9);
            for(int j = (i + 1) % N; j != i; j = (j + 1) % N) {
                if(adj[j][i]) {
                    for(int k = (i + N - 1) % N; k != j; k = (k + N - 1) % N) {
                        if(ans < dp2(i, k, 0) + 2 + mx[k]) {
                            ans = dp2(i, k, 0) + 2 + mx[k];
                            p = j;
                        }
                    }
                }
                for(int k = (i + N - 1) % N; k != j; k = (k + N - 1) % N) {
                    if(adj[k][j]) {
                        mx[k] = max(mx[k], dp1(i, j, 0));
                    }
                }
            }
        }
    }
    //*/

    printf("%d\n%d", ans, p + 1);
}

Compilation message (stderr)

race.cpp: In function 'int main()':
race.cpp:61:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &N, &T);
     ~~~~~^~~~~~~~~~~~~~~~~
race.cpp:65:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             int t; scanf("%d", &t);
                    ~~~~~^~~~~~~~~~

• Subtask 1: 40 / 100