hiho一下 第166周 逃离迷宫

http://hihocoder.com/contest/hiho166/problem/1

用x, y, key描述状态，key二进制表示的第i为为1时表示已经拥有了第i把钥匙。

不知道为啥只过了70/100，TLE了

#include <iostream>#include <string>#include <vector>#include <queue>#include <unordered_map>#include <algorithm>#include <stdio.h>using namespace std;char board[105][105];int n, m, k;int sRow, sCol, eRow, eCol;//int keyRow[6], keyCol[6];int dr[4] = { 0, 0, 1, -1 };int dc[4] = { -1, 1, 0, 0 };bool visited[105][105][32];unordered_map<uint64_t, int> keyPos;struct point {    int r, c, key, step;    point() {}    point(int _r, int _c, int _k, int _s) : r(_r), c(_c), key(_k), step(_s) {}};void addKey(int & key, int i) {    key |= 1 << i;}bool valid(int r, int c, int key) {    if (visited[r][c][key]) {        return false;    }    if (r < 0 || r >= n || c < 0 || c >= m || board[r][c] == '#') {        return false;    }    if (board[r][c] == '.') {        return true;    }    int i = board[r][c] - 'A';    return key & (1 << i);}int bfs(int _sRow, int _sCol, int _eRow, int _eCol) {    queue<point> Q;    int init_key = 0;    /*    for (int i = 0; i < k; ++i) {        if (sRow == keyRow[i] && sCol == keyCol[i]) {            addKey(init_key, i);        }    }*/    uint64_t tmpK = static_cast<uint64_t>(_sRow) << 32 | static_cast<uint64_t>(_sCol);    if (keyPos.find(tmpK) != keyPos.end()) {        addKey(init_key, keyPos[tmpK]);    }    point begin(_sRow, _sCol, init_key, 0);    visited[_sRow][_sCol][init_key] = true;    Q.push(begin);    int ans = -1;    while (!Q.empty()) {        point cur = Q.front();        Q.pop();        //cout << "pos : r : " << cur.r << " c : " << cur.c << " key " << cur.key << endl;        if (cur.r == _eRow && cur.c == _eCol) {            ans = cur.step;            return ans;        }        visited[cur.r][cur.c][cur.key] = true;        for (int i = 0; i < 4; ++i) {            int r = cur.r + dr[i], c = cur.c + dc[i];            if (valid(r, c, cur.key)) {                int tmpKey = cur.key;                /*                for (int j = 0; j < k; ++j) {                    if (r == keyRow[j] && c == keyCol[j]) {                        addKey(tmpKey, j);                    }                }*/                uint64_t tmpK = static_cast<uint64_t>(r) << 32 | static_cast<uint64_t>(c);                if (keyPos.find(tmpK) != keyPos.end()) {                    addKey(tmpKey, keyPos[tmpK]);                }                point tmp(r, c, tmpKey, cur.step + 1);                Q.push(tmp);            }        }    }    return ans;}int main() {    //while (scanf("%d %d %d %d %d %d %d", &n, &m, &k, &sRow, &sCol, &eRow, &eCol) != EOF) {    //cin >> n >> m >> k >> sRow >> sCol >> eRow >> eCol;    while(cin >> n >> m >> k >> sRow >> sCol >> eRow >> eCol){        for (int i = 0; i < n; ++i) {            for (int j = 0; j < m; ++j) {                cin >> board[i][j];            }        }        for (int i = 0; i < k; ++i) {            //cin >> keyRow[i] >> keyCol[i];            int r, c;            //cin >> r >> c;            scanf("%d %d", &r, &c);            uint64_t tmpK = static_cast<uint64_t>(r) << 32 | static_cast<uint64_t>(c);            keyPos[tmpK] = i;        }        memset(visited, false, sizeof(visited));        int ans = bfs(sRow, sCol, eRow, eCol);        //cout << ans << endl;        printf("%d\n", ans);        //cin >> n;    }    return 0;}