Submission #612667

#	Time	Username	Problem	Language	Result	Execution time	Memory
612667		AugustinasJucas	Swapping Cities (APIO20_swap)	C++14	13 / 100	347 ms	41812 KiB

swap

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

vector<pair<int, pair<int, int> > > brn;
const int dydis = 1e5 + 10;
int tevas[dydis];
int kadaNelinija[dydis];
bool neraLinija[dydis] = {};
vector<int> nodes[dydis];
int A[dydis], B[dydis];
int n, m;
vector<pair<int, int> > gr[dydis];
void add(int a, int b, int w) {
    //cout << "brn " << a << " -- " << b << ", w = " << w << endl;
    gr[a].push_back({b, w});
    gr[b].push_back({a, w});
}
int fp(int v) {
    if(tevas[v] == v) return v;
    return tevas[v] = fp(tevas[v]);
}
void conn(int a, int b, int t) {
    int inA = a; int inB = b;

    a = fp(a);
    b = fp(b);
 //   //cout << "jungiu " << inA << "(yra_linija = " << !neraLinija[a] <<") su " << inB  << "(yra_linija = " << !neraLinija[b] << ")" << endl;
    if(a == b) {
        if(neraLinija[a]) return ;
        neraLinija[a] = true;
        for(auto x : nodes[a]) kadaNelinija[x] = t;
    }else {
        add(inA, inB, t);
        if(neraLinija[a] || neraLinija[b]) {
            if(!neraLinija[a]) for(auto x : nodes[a]) kadaNelinija[x] = t;
            if(!neraLinija[b]) for(auto x : nodes[b]) kadaNelinija[x] = t;
        }
        if(nodes[a].size() > nodes[b].size()) swap(a, b);
        // a ---> b

        if(!neraLinija[a] && !neraLinija[b]) {
            set<int> galai = {A[a], B[a], A[b], B[b]};
            ////cout << "linju galai: "; for(auto x : galai) //cout << x << " ";
          //  //cout << ", o as jungiu " << inA << " su " << inB << endl;
            if(galai.count(inA) && galai.count(inB)) {
                /// sujungiau liniju galus
                int na, nb;
                if(A[a] == inA || A[a] == inB) {
                    na = B[a];
                }else {
                    na = A[a];
                }
                if(A[b] == inA || A[b] == inB) {
                    nb = B[b];
                }else {
                    nb = A[b];
                }
                A[b] = na;
                B[b] = nb;
            }else {
                for(auto x : nodes[a]) kadaNelinija[x] = t;
                for(auto x : nodes[b]) kadaNelinija[x] = t;
                neraLinija[b] = true;
            }
        }

        tevas[a] = b;
        for(auto x : nodes[a]) nodes[b].push_back(x);

    }
}
int dbInd = 0;
int enter[dydis], leave[dydis];
int rotW[dydis], par[dydis];
int h[dydis];
void dfs(int v, int came) {
    enter[v] = dbInd++;
    par[v] = came;
   // //cout << "esi " << v << endl;
    for(auto x : gr[v]) {
        if(x.first == came) continue;
        h[x.first] = h[v] + 1;
        rotW[x.first] = x.second;
        //cout << "rot[" << x.first << "] = " << x.second <<  ", T./Y., " << rotW[x.first] << endl;

        dfs(x.first, v);
    }
    leave[v] = dbInd++;
}
const int dd = 10;
int lft[dydis][dd];
int mx[dydis][dd];
void calc() {
    for(int i = 0; i < n; i++) {
        lft[i][0] = par[i];
        //cout << "rotw[" << i << "] = " << rotW[i] << endl;
        mx[i][0] = rotW[i];
        //cout << "mx[" << i << "][" << 0 << "] = " << mx[i][0] << endl;
    }
    for(int j = 1; j < dd; j++) {
        for(int i = 0; i < n; i++) {
            lft[i][j] = lft[lft[i][j-1]][j-1];
        }
    }
    for(int j = 1; j < dd; j++) {
        for(int i = 0; i < n; i++) {
            mx[i][j] = max(mx[i][j-1], mx[ lft[i][j-1] ][j-1]);
            //cout << "mx[" << i << "][" << j << "] = " << mx[i][j] << endl;
        }
    }

}
bool isAnc(int a, int b) {
    return (enter[a] <= enter[b] && leave[b] <= leave[a]);
}

int lca(int a, int b) {
    if(isAnc(a, b)) return a;
    if(isAnc(b, a)) return b;
    for(int i = dd-1; i > -1; i--) {
        if(!isAnc(lft[a][i], b)) {
            a = lft[a][i];
        }
    }
    return par[a];
}

int mxPerBrn(int a, int kek) {
    int ret = 0;
    for(int i = dd-1; i > -1; i--) {
        if((1 << i) <= kek) {
            ret = max(ret, mx[a][i]);
            a = lft[a][i];
            kek -= (1 << i);
        }
    }
    return ret;
}
int mxInPath(int a, int b) {
    int v = lca(a, b);
    int kair = mxPerBrn(a, h[a] - h[v]);
    int desn = mxPerBrn(b, h[b] - h[v]);
    return max(kair, desn);
}

void init(int N, int M,
          std::vector<int> U, std::vector<int> V, std::vector<int> W) {
    n = N; m = M;
    for(int i = 0; i < n; i++)  {
        tevas[i] = i;
        nodes[i] = {i};
        A[i] = i; B[i] = i;
        neraLinija[i] = false;
        kadaNelinija[i] = -1;
    }

    for(int i = 0; i < m; i++) {
        brn.push_back({W[i], {U[i], V[i]}});
    }
    sort(brn.begin(), brn.end()); /// nuo maz iki did.

    for(auto x : brn) {
        int a = x.second.first;
        int b = x.second.second;
        int w = x.first;
        conn(a, b, w);
    }
    h[0] = 0;
    dfs(0, 0);
    calc();

    for(int i = 0; i < n; i++) {
        //cout << "virsune nr " << i << " tampa nebe linija, kai w = " << kadaNelinija[i] << endl;
    }

    for(int i = 0; i < n; i++) {
        for(int j = i+1; j < n; j++) {
            int res = mxInPath(i, j);
            //cout << "min max val tarp " << i << " ir " << j << " yra " << res << endl;
        }
        //cout << endl;
    }


}

int getMinimumFuelCapacity(int X, int Y) {
    if(kadaNelinija[fp(X)] == -1 || kadaNelinija[fp(Y)] == -1) return -1;
    int ret = mxInPath(X, Y);
    ret = max(ret, max(kadaNelinija[fp(X)], kadaNelinija[fp(Y)]));
    return ret;
}

Compilation message (stderr)

swap.cpp: In function 'void init(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
swap.cpp:179:17: warning: unused variable 'res' [-Wunused-variable]
  179 |             int res = mxInPath(i, j);
      |                 ^~~

• Subtask 1: 6 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 17
• Subtask 4: 0 / 20
• Subtask 5: 0 / 23
• Subtask 6: 0 / 27