Submission #1066160

#	Time	Username	Problem	Language	Result	Execution time	Memory
1066160		sammyuri	The Kingdom of JOIOI (JOI17_joioi)	C++17	0 / 100	9 ms	4540 KiB

joioi

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


int height[4][2005][2005];
bool taken[2005][2005];
int h, w;
bool check(int limit, int index) {
    memset(taken, false, sizeof(taken));
    // first row
    taken[0][0] = true;
    for (int j = 1; j < w; j ++) {
        if (abs(height[index][0][j] - height[index][0][j - 1]) <= limit)
            taken[0][j] = true;
        else
            break;
    }
    // subsequent rows
    for (int i = 1; i < h; i ++) {
        // ended
        if (abs(height[index][i][0] - height[index][i - 1][0]) > limit)
            break;
        taken[i][0] = true;
        for (int j = 1; j < w; j ++) {
            if (taken[i - 1][j] && abs(height[index][0][j] - height[index][0][j - 1]) <= limit)
                taken[0][j] = true;
            else
                break;
        }
    }
    // check the rest is ok
    for (int i = 0; i < h; i ++)
        for (int j = 0; j < w - 1; j ++)
            if (!taken[i][j] && !taken[i][j + 1])
                if (abs(height[index][i][j] - height[index][i][j + 1]) > limit)
                    return false;
    for (int j = 0; j < w; j ++)
        for (int i = 0; i < h - 1; i ++)
            if (!taken[i][j] && !taken[i + 1][j])
                if (abs(height[index][i][j] - height[index][i + 1][j]) > limit)
                    return false;
    return true;
}
bool possible(int limit) {
    if (check(limit, 0))
        return true;
    if (check(limit, 1))
        return true;
    if (check(limit, 2))
        return true;
    if (check(limit, 3))
        return true;
    return false;
}


int main() {
    cin >> w >> h;
    for (int i = 0; i < h; i ++) {
        for (int j = 0; j < w; j ++)    
            cin >> height[0][i][j];
    }
    for (int i = 0; i < h; i ++)
        for (int j = 0; j < w; j ++)
            height[1][i][j] = height[0][h - i - 1][j],
            height[2][i][j] = height[0][i][w - j - 1],
            height[3][i][j] = height[0][h - i - 1][w - j - 1];

    int L = 0, R = 1e9 + 5;
    while (L != R) {
        int mid = (L + R) / 2;
        if (possible(mid))
            R = mid;
        else
            L = mid + 1;
    }
    cout << L << endl;
}

• Subtask 1: 0 / 15
• Subtask 2: 0 / 45
• Subtask 3: 0 / 40