Submission #248823

#	Time	Username	Problem	Language	Result	Execution time	Memory
248823		LittleFlowers__	Rectangles (IOI19_rect)	C++17	10 / 100	6 ms	640 KiB

rect

#include <bits/stdc++.h>
using namespace std;
#define in ({int x=0;int c=getchar(),n=0;for(;!isdigit(c);c=getchar()) n=(c=='-');for(;isdigit(c);c=getchar()) x=x*10+c-'0';n?-x:x;})
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
int rnd(int l,int r){return l+rng()%(r-l+1);}
#define fasty ios_base::sync_with_stdio(0),cin.tie(0);
#define forinc(a,b,c) for(int a=b,_c=c;a<=_c;++a)
#define fordec(a,b,c) for(int a=b,_c=c;a>=_c;--a)
#define forv(a,b) for(auto&a:b)
#define fi first
#define se second
#define pb push_back
#define ii pair<int,int>
#define mt make_tuple
#define all(a) a.begin(),a.end()
#define reset(f, x) memset(f, x, sizeof(f))
#define gg exit(0);

const int N=2510;

int m,n;
int a[N][N];
int rt[N][N], lf[N][N], dw[N][N];

long long count_rectangles(vector<vector<int>> arr){
    m=arr.size(), n=arr[0].size();
    forinc(i,1,m) forinc(j,1,n) a[i][j]=arr[i-1][j-1];


    forinc(i,1,m){
        stack<int> w;
        fordec(j,n,1){
            while(w.size() && a[i][j]>a[i][w.top()]) w.pop();
            if(i==2 && j==2){
                //cerr<<a[i][j]<<" "<<a[i][w.top()];
                //cerr<<w.top()<<"\n";
                //gg
            }
            rt[i][j]=w.size() ? w.top() : 0;
            while(w.size() && a[i][j]==a[i][w.top()]) w.pop();
            w.push(j);
        }
        while(w.size()) w.pop();
        forinc(j,1,n){
            while(w.size() && a[i][j]>a[i][w.top()]) w.pop();
            lf[i][j]=w.size() ? w.top() : 0;
            while(w.size() && a[i][j]==a[i][w.top()]) w.pop();
            w.push(j);
        }
    }

    forinc(j,1,n){
        stack<int> w;
        fordec(i,m,1){
            while(w.size() && a[i][j]>=a[w.top()][j]) w.pop();
            dw[i][j]=w.size() ? w.top() : 0;
            w.push(i);
        }
    }

    forinc(i,1,m){
        forinc(j,1,n){
            //cout<<rt[i][j]<<" ";
        }
        //cout<<"\n";
    }

    if(m==3){
        int tot=0;
        forinc(i,2,n-1) if(a[2][i]<a[1][i] && a[2][i]<a[3][i]){
            int j=i;
            while(j<n && a[2][j]<a[1][j] && a[2][j]<a[3][j]){
                if(i==4){
                    //cerr<<lf[2][j+1];
                    //gg/
                }
                tot+=rt[2][i-1]==j+1 || lf[2][j+1]==i-1;
                if(rt[2][i-1]==j+1 || lf[2][j+1]==i-1){
                    //cerr<<i<<" "<<j<<"\n";
                    //cerr<<rt[2][i-1];
                    //gg
                }
                j++;
            }
        }
        return tot;
    }
}

#ifdef UNX
main(){
    #define task "TASK"
    if(fopen(task".inp","r")){
        freopen(task".inp","r",stdin);
        //freopen(task".out","w",stdout);
    }

    int m,n; cin>>m>>n;
    vector<vector<int>> a(m,vector<int>(n));
    forv(i,a) forv(j,i) cin>>j;
    cout<<count_rectangles(a);
}
#endif // UNX

Compilation message (stderr)

rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:88:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^

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