Submission #329767

#	Time	Username	Problem	Language	Result	Execution time	Memory
329767		jebouin	Connecting Supertrees (IOI20_supertrees)	C++17	40 / 100	279 ms	32876 KiB

supertrees

#include "supertrees.h"

#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = (a); i <= (b); i++)
#define rng(a) a.begin(), a.end()
#define ina(n,a) cin >> n; for(int i = 1; i <= n; i++) cin >> a[i]
#define sz(x) (int)(x).size()
#define se second
#define fi first
#define prev            coyhhhhhhyoc    
#define next          sdNNNmNNNNNNNmds  
#define y0           hNNNNy_yNNNNNN_sNh
#define y1          mNNNNNdtdNNNNNNtsNNm
#define yn          mNNNNNNNNy___smNNNms
#define tm            oooooosyysooooot 
#define read               tyhyt        
#define rank              ytmNmo         
#define index              yyy
#define pb push_back
#define pcnt __builtin_popcountll
#define rrep(i,a,b) for(int i = (b); i >= (a); i--)
#define rall(x,a) for(auto x : a)
#define MOD 1000000007
#define endl "\n"
typedef long long ll;
using namespace std;

const int N = 1111;
int p[N][N], b[N][N], dsu[N], rank[N];
int n;

int solve1() {
    rep(i, 1, n - 1) {
        int ii = i % n + 1;
        b[i][ii] = 1;
        b[ii][i] = 1;
    }
    return 1;
}

int find(int u) {
    if(dsu[u] == u) return u;
    dsu[u] = find(dsu[u]);
    return dsu[u];
}

bool merge(int u, int v) {
    u = find(u), v = find(v);
    if(u == v) return false;
    if(rank[u] > rank[v]) {
        dsu[v] = u;
    } else {
        dsu[u] = v;
        if(rank[u] == rank[v]) {
            rank[v]++;
        }
    }
    return true;
}

int solve23() {
    rep(i, 1, n) {
        dsu[i] = i;
    }
    rep(i, 1, n) {
        rep(j, 1, n) {
            if(p[i][j]) {
                merge(i, j);
            }
        }
    }
    return 1;
}

int solve2() {
    if(!solve23()) {
        return 0;
    }
    rep(i, 1, n) {
        rep(j, 1, n) {
            int u = find(i), v = find(j);
            if((u == v) != p[i][j]) {
                return 0;
            }
        }
    }
    rep(u, 1, n) {
        int v = find(u);
        if(u != v) {
            b[u][v] = 1;
            b[v][u] = 1;
        }
    }
    return 1;
}

int solve3() {
    if(!solve23()) {
        return 0;
    }
    vector<vector<int> > gps(n + 1);
    rep(u, 1, n) {
        int r = find(u);
        gps[r].pb(u);
    }
    rep(i, 1, n) {
        rep(j, i + 1, n) {
            int u = find(i), v = find(j);
            if((u == v) != (p[i][j] == 2)) {
                return 0;
            }
            if(p[i][j] == 2 && sz(gps[u]) < 3) {
                return 0;
            }
        }
    }
    rep(r, 1, n) {
        int k = sz(gps[r]);
        rep(i, 0, k - 1) {
            int u = gps[r][i], v = gps[r][(i + 1) % k];
            if(u != v) {
                b[u][v] = 1;
                b[v][u] = 1;
            }
        }
    }
    return 1;
}

int construct(vector<vector<int>> in) {
    n = sz(in);
    bool task1 = true, task2 = true, task3 = true;
    rep(i, 1, n) {
        rep(j, 1, n) {
            p[i][j] = in[i - 1][j - 1];
            if(i != j) {
                if(p[i][j] != 1) {
                    task1 = false;
                }
                if(p[i][j] > 1) {
                    task2 = false;
                }
                if(p[i][j] != 0 && p[i][j] != 2) {
                    task3 = false;
                }
            }
        }
    }
    bool ret;
    if(task1) {
        ret = solve1();
    } else if(task2) {
        ret = solve2();
    } else if(task3) {
        ret = solve3();
    }
    if(ret) {
        vector<vector<int> > ans(n, vector<int>(n));
        rep(i, 1, n) {
            rep(j, 1, n) {
                ans[i - 1][j - 1] = b[i][j];
            }
        }
        build(ans);
        return 1;
    }
	return 0;
}

Compilation message (stderr)

supertrees.cpp: In function 'int construct(std::vector<std::vector<int> >)':
supertrees.cpp:157:5: warning: 'ret' may be used uninitialized in this function [-Wmaybe-uninitialized]
  157 |     if(ret) {
      |     ^~

• Subtask 1: 11 / 11
• Subtask 2: 10 / 10
• Subtask 3: 19 / 19
• Subtask 4: 0 / 35
• Subtask 5: 0 / 21
• Subtask 6: 0 / 4