Submission #836724

#	Time	Username	Problem	Language	Result	Execution time	Memory
836724		nigus	Paint By Numbers (IOI16_paint)	C++17	100 / 100	292 ms	186472 KiB

paint

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

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define trav(a, x) for(auto& a : x)
#define all(x) x.begin(), x.end()
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<ll> vl;

const int MAXN = 200004;
const int MAXK = 104;

vi A;
vi C;
vi CSB, CSW;
int n,k;

bool DP[MAXK][MAXN] = {0};
int DPC[MAXK][MAXN] = {0};

int NEXTB[MAXN] = {0};

int wh(int lo, int hi){
    if(lo > hi)return 0;
   return CSW[hi+1]-CSW[lo]; 
}

int bl(int lo, int hi){
    if(lo > hi)return 0;
    return CSB[hi+1]-CSB[lo];
}

int CW[MAXN] = {0};
int CB[MAXN] = {0};

int ANS[MAXN] = {0};

string alf = "X_?";

int PREV[MAXK][MAXN] = {0};

void add_w(int i, int j){
    if(i > j)return;
 //   cerr << "WHITE " << i << " " << j << "\n";
    CW[i]++;
    CW[j+1]--;
}

void add_b(int i, int j){
    if(i > j)return;
  //  cerr << "BLACK " << i << " " << j << "\n";
    CB[i]++;
    CB[j+1]--;
}


int bla[2][MAXN] = {0};
void add_int(int i, int j, int b){
    bla[b][i]++;
    bla[b][j+1]--;
}


std::string solve_puzzle(string s, vector<int> c) {
    n = sz(s);
    k = sz(c);
    C = c;
    rep(c1,0,n){
        if(s[c1] == 'X'){
            // black
            A.push_back(0);
        }
        if(s[c1] == '_'){
            // white
            A.push_back(1);
        }
        if(s[c1] == '.'){
            A.push_back(2);
        }
    }


    bool DEBUG = 0;

    CSB.clear();
    CSW.clear();
    CSB.push_back(0);
    CSW.push_back(0);
    rep(c1,0,n){
        CSB.push_back(CSB.back() + (A[c1] == 0));
        CSW.push_back(CSW.back() + (A[c1] == 1));
    }

    rep(c1,0,n+1){
        rep(c2,0,k+1){
            DP[c2][c1] = 0;
        }
    }

    int nex = n;
    NEXTB[n] = n;
    for(int c1 = n-1; c1 >= 0; c1--){
        if(A[c1] == 0)nex = c1;
        NEXTB[c1] = nex;
    }

    for(int i = n; i >= C[k-1]; i--){
        if(i < n && A[i] == 0)break;
        DP[k][i] = ((wh(i-C[k-1],i-1) == 0));
    }

    DPC[k][0] = 0;
    rep(c1,0,n+1){
        DPC[k][c1+1] = (DPC[k][c1] + DP[k][c1]);
    }

    for(int j = k-1; j >= 0; j--){
        int c0 = 0;
        if(j > 0){
            c0 = C[j-1];
        }
        for(int i = c0+(j > 0); i < n; i++){
            if(j == 0 || (A[i-1] != 0 && wh(i-1-c0,i-2) == 0)){
                int lo = i + C[j] + (j < k-1);
                int hi = NEXTB[i] + C[j] + (j < k-1);
                hi = min(hi, n);
                if(lo <= hi){
                    DP[j][i] = (DPC[j+1][hi+1] - DPC[j+1][lo] > 0);
                }
            }
        }
        DPC[j][0] = 0;
        rep(c1,0,n+1){
            DPC[j][c1+1] = (DPC[j][c1] + DP[j][c1]);
        }
    }

    if(DEBUG){
    rep(c1,0,k+1){
        rep(c2,0,n+1){
            cerr << DP[c1][c2] << " ";
        }
        cerr << "\n";
    }
    }
  
    
    rep(j,0,k+1){
        int prev = -1;
        rep(i,0,n+1){
            if(DP[j][i])prev = i;
            PREV[j][i] = prev;
        }
    }

    add_int(0,0,0);
    rep(j,0,k+1){

        int w = 0;
        rep(i,0,n+1){
            bla[(j+1)%2][i] = 0;
        }
        rep(i,0,n+1){
                w += bla[j%2][i];

                if(w > 0 && (DP[j][i])){
                  //  cerr << j << " - " << i << "\n";
                    if(j == k){
                        add_w(i,n);
                        add_b(i-C[j-1],i-1);
                    }
                    else{
                        if(j > 0){
                            add_w(i-1,i-1);
                            add_b(i-1-C[j-1],i-2);
                        }
                        else{
                            add_w(0, i-1);
                        }
                    }

                    //if(j == k)continue;

                    int lo = i + C[j] + (j < k-1);
                    int hi = NEXTB[i] + C[j] + (j < k-1);
                    hi = min(hi, n);
                  //  intervals2.push_back({lo,hi});

                    add_int(lo,hi,(j+1)%2);

                    int furthest = PREV[j+1][hi];
                    add_w(i, furthest - C[j] - (j < k-1) - 1);

                }
                
            
            
        }
  
    }

    int w = 0;
    int b = 0;
    rep(c1,0,n){
        w += CW[c1];
        b += CB[c1];
        if(b > 0){
            ANS[c1] ^= 1;
        }
        if(w > 0){
            ANS[c1] ^= 2;
        }
    }
    rep(c1,0,n){
        ANS[c1]--;
    }


    string ans = "";
    rep(c1,0,n){
      //  cerr << ANS[c1] << "\n";
        ans += alf[ANS[c1]];
    }
    return ans;
}

• Subtask 1: 7 / 7
• Subtask 2: 3 / 3
• Subtask 3: 22 / 22
• Subtask 4: 27 / 27
• Subtask 5: 21 / 21
• Subtask 6: 10 / 10
• Subtask 7: 10 / 10