sgu335.cpp

SGU335题解。一道要考虑一些情况的题目。CPP程序。

#include <cctype>
#include <iostream>
#include <algorithm>

using namespace std;

typedef long long Int64;

const Int64 inf = 1000000000000000LL;
const int dire[4][2] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};

int H, W, r1, c1, r2, c2;
char start;

inline bool Outside(int x, int y) {
    return x < 0 || y < 0 || x >= H || y >= W;
}

Int64 Calc(int H, int W, int r1, int c1, int r2, int c2) {
    if (c1 < c2) {
        c1 = W - 1 - c1;
        c2 = W - 1 - c2;
    }
    if (r1 < r2) {
        r1 = H - 1 - r1;
        r2 = H - 1 - r2;
    }
    if (c1 - c2 > r1 - r2) {
        swap(r1, c1);
        swap(r2, c2);
        swap(H, W);
    }
    if (r1 == r2 && c1 == c2) return 0;
    if (W == 1) {
        //cout << r2 << " " << r1 << endl;
        Int64 res = 0;
        res += r2 * 2;
        r1 -= r2;
        r2 = 0;
        int ss;
        if (r1 > 5) {
            ss = (r1 - 5) / 2;
            res += ss * 4;
            r1 -= ss * 2;
        }
        //cout << r1 << endl;
        while (r1 != r2) {
            res++;
            if (r2 == 0) r2++;
            else r2--;
            if (r1 == r2) break;
            res++;
            r1--;
            if (r1 == r2) break;
        }
        return res;
    }
    if (((r1 - r2) + (c1 - c2)) & 1) return inf;
    Int64 res1 = 0, res2 = 0;
    //cout << r1 << " " << c1 << " " << r2 << " " << c2 << endl;
    //cout << H << " " << W << endl;
    int rr1 = r1, cc2 = c2;
    if (c1 > 0) {
        res1 = 0;
        if (c1 == c2) {
            res1 += 2;
            c2--;
            r1--;
        }
        res1 += (c1 - c2 - 1) * 2;
        r1 -= c1 - c2 - 1;
        c2 = c1 - 1;
        res1 += (r1 - r2 - 1) * 2;
        res1 += (r2 + c2) * 2;
        res1 += 2;
    }
    r1 = rr1;
    c2 = cc2;
    if (c1 + 1 < W) {
        res2 = 0;
        res2 += (c1 - c2) * 2;
        r1 -= c1 - c2;
        c2 = c1;
        if (r1 == r2) return res1;
        res2 += 2;
        c2++;
        r1--;
        //cout << r1 - r2 - 1 << endl;
        res2 += (r1 - r2 - 1) * 2;
        res2 += (r2 + W - 1 - c2) * 2;
        res2 += 2;
    }
    //cout << res1 << " " << res2 << endl;
    return max(res1, res2);
}

int main() {
    int i, rr, cc;
    Int64 ans;
    while (cin >> H >> W) {
        cin >> r1 >> c1 >> r2 >> c2;
        r1--;
        c1--;
        r2--;
        c2--;
        if ((r1 == r2 && c1 == c2) || Outside(r1, c1) || Outside(r2, c2)) for (; ; );
        cin >> start;
        if (toupper(start) == 'C') {
            ans = inf;
            for (i = 0; i < 4; i++) {
                rr = r1 + dire[i][0];
                cc = c1 + dire[i][1];
                if (Outside(rr, cc)) continue;
                ans = min(ans, Calc(H, W, rr, cc, r2, c2));
            }
            if (ans == inf) cout << 0 << endl;
            else cout << ans + 1 << endl;
        } else {
            ans = Calc(H, W, r1, c1, r2, c2);
            if (ans == inf) cout << 0 << endl;
            else cout << ans << endl;
        }
    }
    return 0;
}