Submission #1031019

#	Time	Username	Problem	Language	Result	Execution time	Memory
1031019		Zicrus	Rectangles (IOI19_rect)	C++17	37 / 100	5059 ms	388580 KiB

rect

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

typedef long long ll;

ll n, m;
ll pow2N, pow2M;
vector<vector<ll>> segN, segM;
 
ll segMaxN(ll low, ll high, ll m) {
    low += pow2N; high += pow2N;
    ll mx = 0;
    while (low <= high) {
        if (low & 1) mx = max(mx, segN[m][low++]);
        if (!(high & 1)) mx = max(mx, segN[m][high--]);
        low /= 2; high /= 2;
    }
    return mx;
}
 
ll segMaxM(ll low, ll high, ll n) {
    low += pow2M; high += pow2M;
    ll mx = 0;
    while (low <= high) {
        if (low & 1) mx = max(mx, segM[n][low++]);
        if (!(high & 1)) mx = max(mx, segM[n][high--]);
        low /= 2; high /= 2;
    }
    return mx;
}

ll count_rectangles(vector<vector<int>> a) {
    if (a.size() <= 2) return 0;
    n = a.size(); m = a[0].size();
    pow2N = 1ll << (ll)ceil(log2(n));
    pow2M = 1ll << (ll)ceil(log2(m));
    vector<int> am = a[1];
    segN = vector<vector<ll>>(m, vector<ll>(2*pow2N));
    segM = vector<vector<ll>>(n, vector<ll>(2*pow2M));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            segN[j][pow2N+i] = a[i][j];
            segM[i][pow2M+j] = a[i][j];
        }
    }
    for (int meta = 0; meta < n; meta++) {
        for (int i = pow2M-1; i > 0; i--) {
            segM[meta][i] = max(segM[meta][2*i], segM[meta][2*i+1]);
        }
    }
    for (int meta = 0; meta < m; meta++) {
        for (int i = pow2N-1; i > 0; i--) {
            segN[meta][i] = max(segN[meta][2*i], segN[meta][2*i+1]);
        }
    }

    unordered_set<ll> s;

    ll res = 0;
    for (int i = 1; i < n-1; i++) {
        for (int j = 1; j < m-1; j++) {
            ll left = j, right = j, top = i, bottom = i;
            ll ref = a[i][j];

            ll low = 0, high = j;
            while (low < high) {
                ll mid = (low + high + 1) / 2;
                if (segMaxM(mid, high, i) <= ref) {
                    high = mid-1;
                }
                else {
                    low = mid;
                }
            }
            left = low+1;
            low = j, high = m-1;
            while (low < high) {
                ll mid = (low + high) / 2;
                if (segMaxM(low, mid, i) <= ref) {
                    low = mid+1;
                }
                else {
                    high = mid;
                }
            }
            right = high-1;
            while (a[top][j] <= ref && top > 0) top--; top++;
            while (a[bottom][j] <= ref && bottom < n-1) bottom++; bottom--;

            ll hash = (left << 48) | (right << 32) | (top << 16) | bottom;
            if (s.count(hash)) continue;
            s.insert(hash);

            ll lN = bottom-top+1, lM = right-left+1;
            bool poss = 1;
            for (int meta = top; meta < top+lN && poss; meta++) {
                ll border = min(a[meta][left-1], a[meta][left+lM]);
                if (border <= segMaxM(left, left+lM-1, meta)) {
                    poss = 0;
                }
            }
            for (int meta = left; meta < left+lM && poss; meta++) {
                ll border = min(a[top-1][meta], a[top+lN][meta]);
                if (border <= segMaxN(top, top+lN-1, meta)) {
                    poss = 0;
                }
            }
            res += poss;
        }
    }
    return res;
}

Compilation message (stderr)

rect.cpp: In function 'll count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:88:13: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   88 |             while (a[top][j] <= ref && top > 0) top--; top++;
      |             ^~~~~
rect.cpp:88:56: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   88 |             while (a[top][j] <= ref && top > 0) top--; top++;
      |                                                        ^~~
rect.cpp:89:13: warning: this 'while' clause does not guard... [-Wmisleading-indentation]
   89 |             while (a[bottom][j] <= ref && bottom < n-1) bottom++; bottom--;
      |             ^~~~~
rect.cpp:89:67: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'while'
   89 |             while (a[bottom][j] <= ref && bottom < n-1) bottom++; bottom--;
      |                                                                   ^~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 7 / 7
• Subtask 3: 12 / 12
• Subtask 4: 0 / 22
• Subtask 5: 10 / 10
• Subtask 6: 0 / 13
• Subtask 7: 0 / 28