Submission #973499

#	Time	Username	Problem	Language	Result	Execution time	Memory
973499		njoop	Portals (BOI14_portals)	C++17	70 / 100	1036 ms	45364 KiB

portals

#include <bits/stdc++.h>

using namespace std;

int r, c, dp[1010][1010], stx, sty, enx, eny, cx, cy, cdi, mn;
int dx[4] = {1, 0, -1, 0}, dy[4] = {0, 1, 0, -1};
char arr[1010][1010];
pair<int, int> dir[4][1010][1010], cur;
queue<tuple<int, int, int>> q;

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> r >> c;
    for(int i=0; i<1010; i++) for(int j=0; j<1010; j++) arr[i][j] = '#';
    for(int i=1; i<=r; i++) {
        for(int j=1; j<=c; j++) {
            cin >> arr[i][j];
            if(arr[i][j] == 'S') {
                stx = i;
                sty = j;
            }
            if(arr[i][j] == 'C') {
                enx = i;
                eny = j;
            }
            dp[i][j] = 1e9;
        }
    }
    for(int j=0; j<=c+1; j++) {
        for(int i=0; i<=r+1; i++) {
            if(arr[i][j] == '#') cur = {i+1, j};
            dir[0][i][j] = cur;
        }
    }
    for(int i=0; i<=r+1; i++) {
        for(int j=0; j<=c+1; j++) {
            if(arr[i][j] == '#') cur = {i, j+1};
            dir[1][i][j] = cur;
        }
    }
    for(int j=0; j<=c+1; j++) {
        for(int i=r+1; i>=0; i--) {
            if(arr[i][j] == '#') cur = {i-1, j};
            dir[2][i][j] = cur;
        }
    }
    for(int i=0; i<=r+1; i++) {
        for(int j=c+1; j>=0; j--) {
            if(arr[i][j] == '#') cur = {i, j-1};
            dir[3][i][j] = cur;
        }
    }
    q.push({stx, sty, 0});
    while(q.size()) {
        cx = get<0>(q.front());
        cy = get<1>(q.front());
        cdi = get<2>(q.front());
        q.pop();
        if(cx < 1 || cx > r || cy < 1 || cy > c || dp[cx][cy] <= cdi || arr[cx][cy] == '#') continue;
        dp[cx][cy] = cdi;
        mn = 1e9;
        for(int i=0; i<4; i++) {
            mn = min(mn, abs(dir[i][cx][cy].first-cx) + abs(dir[i][cx][cy].second-cy));
            q.push({cx+dx[i], cy+dy[i], cdi+1});
        }
        for(int i=0; i<4; i++) {
            q.push({dir[i][cx][cy].first, dir[i][cx][cy].second, cdi+mn+1});
        }
    }
    cout << dp[enx][eny];
    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 20 / 20
• Subtask 3: 20 / 20
• Subtask 4: 19 / 19
• Subtask 5: 0 / 30