Submission #249445

#	Time	Username	Problem	Language	Result	Execution time	Memory
249445		LittleFlowers__	Rectangles (IOI19_rect)	C++17	10 / 100	657 ms	40952 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);
#define y1 ditconmemay

const int N=2510;

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

int top;
int w[N];

int cnt,x1,x2,y1,y2;
int dd[N][N];

void dfs(int i,int j){
    if(1>i||i>m||1>j||j>n||dd[i][j]||a[i][j]) return;
    dd[i][j]=1;
    cnt++;
    x1=min(x1,i), x2=max(x2,i), y1=min(y1,j), y2=max(y2,j);
    dfs(i-1,j);
    dfs(i,j-1);
    dfs(i+1,j);
    dfs(i,j+1);
}

long long count_rectangles(vector<vector<int>> arr){
    m=arr.size(), n=arr[0].size();

    int mx=0;
    forinc(i,1,m) forinc(j,1,n) mx=max(mx,a[i][j]=arr[i-1][j-1]);

    if(mx<=1){
        int tot=0;
        forinc(i,2,m-1){
            forinc(j,2,n-1) if(dd[i][j] + a[i][j] == 0){
                x1=x2=i, y1=y2=j;
                dfs(i,j);
                if(cnt==(x2-x1+1)*(y2-y1+1) && 1<x1&&x2<m && 1<y1&&y2<n)
                    tot++;
            }
        }
        return tot;
    }

    forinc(i,1,m){
        top=0;
        fordec(j,n,1){
            while(top && a[i][j]>a[i][w[top]]) top--;
            rt[i][j]=top ? w[top] : 0;
            while(top && a[i][j]==a[i][w[top]]) top--;
            w[++top]=j;
        }
        top=0;
        forinc(j,1,n){
            while(top && a[i][j]>a[i][w[top]]) top--;
            lf[i][j]=top ? w[top] : 0;
            while(top && a[i][j]==a[i][w[top]]) top--;
            w[++top]=j;
        }
    }

    forinc(j,1,n){
        top=0;
        fordec(i,m,1){
            while(top && a[i][j]>a[w[top]][j]) top--;
            dw[i][j]=top ? w[top] : 0;
            while(top && a[i][j]==a[w[top]][j]) top--;
            w[++top]=i;
        }
        top=0;
        forinc(i,1,m){
            while(top && a[i][j]>a[w[top]][j]) top--;
            up[i][j]=top ? w[top] : 0;
            while(top && a[i][j]==a[w[top]][j]) top--;
            w[++top]=i;
        }
    }

    auto chk=[&](int x,int y,int u,int v){
        if(y-x<2) return 0;
        int suc=1;
        forinc(i,x+1,y-1) if(rt[i][u-1]!=v+1 && lf[i][v+1]!=u-1) return 0;
        return 1;
    };
    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]){
                tot+=rt[2][i-1]==j+1 || lf[2][j+1]==i-1;
                j++;
            }
        }
        return tot;
    } else{
        int tot=0;
        forinc(i,1,m){
            forinc(j,2,n-1){
                if(!to_up[i][j] && up[i][j]){
                    int t=up[i][j];
                    int k=j;
                    int bp=0;
                    while(k<n && (up[i][k]==t || dw[t][k]==i)){
                        if(to_up[i][k] && up[i][k]==t || to_dw[t][k] && dw[t][k]==i){
                            bp=k;
                            k=to_up[i][k] && up[i][k]==t ? to_up[i][k] : to_dw[t][k];
                            break;
                        }
                        k++;
                    }
                    if(!bp) bp=k;
                    forinc(l,j,bp-1){
                        if(up[i][l]==t) to_up[i][l]=k;
                        if(dw[t][l]==i) to_dw[t][l]=k;
                    }
                    forinc(l,j,bp-1) forinc(r,l,k-1) tot+=chk(t,i,l,r);
                }
                if(!to_dw[i][j] && dw[i][j]){
                    int t=dw[i][j];
                    int k=j;
                    int bp=0;
                    while(k<n && (up[t][k]==i || dw[i][k]==t)){
                        if(to_up[t][k] && up[t][k]==i || to_dw[i][k] && dw[i][k]==t){
                            bp=k;
                            k=to_up[t][k] && up[t][k]==i ? to_up[t][k] : to_dw[i][k];
                            break;
                        }
                        k++;
                    }
                    if(!bp) bp=k;
                    forinc(l,j,bp-1){
                        if(up[t][l]==i) to_up[t][l]=k;
                        if(dw[i][l]==t) to_dw[i][l]=k;
                    }
                    forinc(l,j,bp-1) forinc(r,l,k-1) tot+=chk(i,t,l,r);
                }
            }

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

Compilation message (stderr)

rect.cpp: In lambda function:
rect.cpp:99:13: warning: unused variable 'suc' [-Wunused-variable]
         int suc=1;
             ^~~
rect.cpp: In function 'long long int count_rectangles(std::vector<std::vector<int> >)':
rect.cpp:122:40: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                         if(to_up[i][k] && up[i][k]==t || to_dw[t][k] && dw[t][k]==i){
                            ~~~~~~~~~~~~^~~~~~~~~~~~~~
rect.cpp:141:40: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
                         if(to_up[t][k] && up[t][k]==i || to_dw[i][k] && dw[i][k]==t){
                            ~~~~~~~~~~~~^~~~~~~~~~~~~~

• 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