Submission #1109366

#	Time	Username	Problem	Language	Result	Execution time	Memory
1109366		mariaclara	The Kingdom of JOIOI (JOI17_joioi)	C++17	100 / 100	1472 ms	70612 KiB

joioi

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef tuple<ll,ll,ll> trio;
typedef pair<int,int> pii;
const int MAXN = 2e5+5;
const ll INF = 1e9;
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mk make_pair
#define pb push_back
#define fr first
#define sc second

int n, m, max_val, min_val = 1e9, v[2005][2005], color[2005][2005];

bool check(int dif) {

    for(int i = 1; i <= n; i++) {
        for(int j = 1, a, b, c, d; j <= m; j++) {
            color[i][j] = 0;
            if(max_val - dif >= v[i][j]) color[i][j] = 1, a = i, b = j;
            if(min_val + dif <= v[i][j]) color[i][j] = -1, c = i, d = j;
            if(a == c and b == d) return 0;
        }
    }

    bool c_pos = 1, d_pos = 1, c_neg = 1, d_neg = 1;

    for(int i = 1, last_c = 0, last_d = m; i <= n; i++) {
        int At = 0, Max = m;

        for(int j = 1; j <= m; j++) {
            if(color[i][j] == 0) continue;
            if(color[i][j] == 1) At = j;
            else if(j <= Max) Max = j-1;
        }

        last_c = max(last_c, At);
        if(last_c > Max) c_pos = 0;

        last_d = min(last_d, Max);
        if(last_d < At) d_pos = 0;
    }

    for(int i = 1, last_c = 0, last_d = m; i <= n; i++) {
        int At = 0, Max = m;

        for(int j = 1; j <= m; j++) {
            if(color[i][j] == 0) continue;
            if(color[i][j] == -1) At = j;
            else if(j <= Max) Max = j-1;
        }

        last_c = max(last_c, At);
        if(last_c > Max) c_neg = 0;

        last_d = min(last_d, Max);
        if(last_d < At) d_neg = 0;
    }

    return c_pos or d_pos or c_neg or d_neg;
}

int busca() {
    int l = 1, r = max_val - min_val;
    while(l <= r) {
        int mid = (l+r)/2;
        if(check(mid)) r = mid-1;
        else l = mid+1;
    }
    return r;
}
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> m;

    for(int i = 1; i <= n; i++) {
        for(int j = 1; j <= m; j++) {
            cin >> v[i][j];
            min_val = min(min_val, v[i][j]);
            max_val = max(max_val, v[i][j]);
        }
    }

    cout << busca();
}

Compilation message (stderr)

joioi.cpp: In function 'bool check(int)':
joioi.cpp:26:29: warning: 'd' may be used uninitialized in this function [-Wmaybe-uninitialized]
   26 |             if(a == c and b == d) return 0;
      |                           ~~^~~~
joioi.cpp:26:18: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   26 |             if(a == c and b == d) return 0;
      |                ~~^~~~
joioi.cpp:26:29: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   26 |             if(a == c and b == d) return 0;
      |                           ~~^~~~
joioi.cpp:26:18: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
   26 |             if(a == c and b == d) return 0;
      |                ~~^~~~

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