Submission #96447

#	Time	Username	Problem	Language	Result	Execution time	Memory
96447		choikiwon	Bomb (IZhO17_bomb)	C++17	37 / 100	1045 ms	108224 KiB

bomb

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

typedef pair<int, int> pii;

const int MN = 2525;

int dx[4] = {0, 0, 1, -1};
int dy[4] = {1, -1, 0, 0};

int N, M;
char G[MN][MN];

int cc[MN][MN][4];
int dp(int r, int c, int d) {
    if(r < 0 || N <= r || c < 0 || M <= c) return 0;
    int &ret = cc[r][c][d];
    if(ret != -1) return ret;
    if(G[r][c] == '0') return ret = 0;
    return ret = dp(r + dy[d], c + dx[d], d) + 1;
}

vector<int> V[MN];
int mn[MN];

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

    for(int i = 0; i < N; i++) {
        scanf("\n");
        for(int j = 0; j < M; j++) {
            scanf("%c", &G[i][j]);
        }
    }

    memset(cc, -1, sizeof(cc));

    for(int i = 0; i < N; i++) {
        for(int j = 0; j < M; j++) {
            if(G[i][j] == '1' && dp(i, j, 0) == 1) {
                V[i].push_back(j);
            }
        }
    }

    int mnw = 1e9;
    for(int i = 0; i < N; i++) for(int j = 0; j < M; j++) if(G[i][j] == '1') {
        mnw = min(mnw, dp(i, j, 2) + dp(i, j, 3) - 1);
    }

    for(int i = 0; i <= mnw; i++) mn[i] = 1e9;
    for(int i = 0; i < N; i++) for(int j = 0; j < M; j++) if(G[i][j] == '1') {
        int a = lower_bound(V[i].begin(), V[i].end(), j) - V[i].begin();
        int b = a - 1;
        int l = j - dp(i, j, 3) + 1;
        int r = j + dp(i, j, 2) - 1;

        if(a != V[i].size() && V[i][a] <= r) {
            mn[ V[i][a] - j + 1 ] = min(mn[ V[i][a] - j + 1 ], dp(i, j, 1));
        }
        if(b != -1 && l <= V[i][b]) {
            mn[ j - V[i][b] + 1 ] = min(mn[ j - V[i][b] + 1 ], dp(i, j, 1));
        }
    }
    int ans = 0;
    for(int i = 1; i <= mnw; i++) {
        mn[i] = min(mn[i], mn[i - 1]);
        ans = max(ans, mn[i] * i);
    }
    printf("%d", ans);
}

Compilation message (stderr)

bomb.cpp: In function 'int main()':
bomb.cpp:58:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(a != V[i].size() && V[i][a] <= r) {
            ~~^~~~~~~~~~~~~~
bomb.cpp:27:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &N, &M);
     ~~~~~^~~~~~~~~~~~~~~~~
bomb.cpp:30:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("\n");
         ~~~~~^~~~~~
bomb.cpp:32:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
             scanf("%c", &G[i][j]);
             ~~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 37 / 100