Submission #207645

#	Time	Username	Problem	Language	Result	Execution time	Memory
207645		PeppaPig	Robots (APIO13_robots)	C++14	30 / 100	1591 ms	52728 KiB

robots

#include <bits/stdc++.h>

#define pii pair<int, int>
#define x first
#define y second

using namespace std;

const int N = 505;
const int dx[4] = {1, 0, -1, 0};
const int dy[4] = {0, -1, 0, 1};

struct item {
    int r, c, id;
    item(int r, int c, int id) : r(r), c(c), id(id) {}
};

int n, w, h, dp[N][N][40];
char A[N][N];
pii nex[N][N][4];
map<pii, int> mp;

pii find_next(int r, int c, int dir) {
    if(nex[r][c][dir] == pii(-1, -1) && A[r][c] != 'x') {
        int ndir = dir;
        if(A[r][c] == 'C') ndir = (dir + 1) % 4;
        if(A[r][c] == 'A') ndir = (dir + 3) % 4;
        int nr = r + dx[ndir], nc = c + dy[ndir];
        if(nr < 1 || nr > h || nc < 1 || nc > w || A[nr][nc] == 'x')
            nex[r][c][dir] = pii(r, c);
        else nex[r][c][dir] = find_next(nr, nc, ndir);
    }
    return nex[r][c][dir];
}

int main() {
    fill_n(nex[0][0], N * N * 4, pii(-1, -1));
    fill_n(dp[0][0], N * N * 40, 1e9);

    scanf("%d %d %d", &n, &w, &h);
    for(int i = 1; i <= h; i++) scanf(" %s", A[i] + 1);

    for(int i = 1; i <= h; i++) 
        for(int j = 1; j <= w; j++)
            for(int k = 0; k < 4; k++)
                find_next(i, j, k);
    for(int i = 1, ptr = 0; i <= n; i++) for(int j = i; j <= n; j++)
        mp[pii(i, j)] = ++ptr;

    for(int k = 1; k <= n; k++) {
        queue<item> Q;
        for(int i = 1; i <= h; i++) for(int j = 1; j <= w; j++) {
            if(A[i][j] == 'x') continue;
            if(k == 1) {
                if('1' <= A[i][j] && A[i][j] <= '9') {
                    int now = mp[pii(A[i][j] - '0', A[i][j] - '0')];
                    Q.emplace(i, j, now);
                    dp[i][j][now] = 0;
                }
            } else {
                for(int x = 1, y = k; y <= n; x++, y++) {
                    int now = mp[pii(x, y)];
                    for(int l = x; l < y; l++) {
                        int L = mp[pii(x, l)], R = mp[pii(l + 1, y)];
                        dp[i][j][now] = min(dp[i][j][now], dp[i][j][L] + dp[i][j][R]);
                    }
                    Q.emplace(i, j, now);
                }
            }
        }
        while(!Q.empty()) {
            item u = Q.front(); Q.pop();
            if(k == 1) {
                pii now;
                for(auto p : mp) if(p.y == u.id) now = p.x;
                // printf("now at %d %d (%d %d)\n", u.r, u.c, now.x, now.y);
                // printf("push = %d\n", dp[u.r][u.c][u.id]);
            }
            for(int i = 0; i < 4; i++) {
                int nr = u.r + dx[i], nc = u.c + dy[i];
                if(nr < 1 || nr > h || nc < 1 || nc > w || A[nr][nc] == 'x')
                    continue;
                pii v = nex[nr][nc][i];
                // if(k == 1) printf("nex %d = (%d %d)", i, v.x, v.y);
                if(dp[u.r][u.c][u.id] + 1 < dp[v.x][v.y][u.id]) {
                    dp[v.x][v.y][u.id] = dp[u.r][u.c][u.id] + 1;
                    Q.emplace(v.x, v.y, u.id);
                }
            }
        }
    }
    int ans = 1e9;
    for(int i = 1; i <= h; i++) for(int j = 1; j <= w; j++)
        ans = min(ans, dp[i][j][mp[pii(1, n)]]); 
    if(ans != 1e9) printf("%d\n", ans);
    else printf("-1\n");

    // printf("(%d %d)\n", nex[4][7][2].x, nex[4][7][2].y);

    return 0;
}

Compilation message (stderr)

robots.cpp: In function 'int main()':
robots.cpp:40:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &n, &w, &h);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
robots.cpp:41:38: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 1; i <= h; i++) scanf(" %s", A[i] + 1);
                                 ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 20 / 20
• Subtask 3: 0 / 30
• Subtask 4: 0 / 40