Submission #428571

#	Time	Username	Problem	Language	Result	Execution time	Memory
428571		tqbfjotld	Cheerleaders (info1cup20_cheerleaders)	C++14	72 / 100	2052 ms	74772 KiB

cheerleaders

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

int arr[(1<<18)+5];
int curarr[(1<<18)+5];

vector<int> f1(vector<int> v){
    vector<int> nw;
    for (int x = 0; x<v.size(); x+=2){
        nw.push_back(v[x]);
    }
    for (int x = 1; x<v.size(); x+=2){
        nw.push_back(v[x]);
    }
    return nw;
}

int n,logn;

vector<long long> allvals(int lpos, int sz ,vector<pair<int,int> > sorted){
    if (sorted.size()==1){
        return {0};
    }
   // printf("called with sz %d, sortsz %d\n",sz,sorted.size());
    long long inter1 = 0,inter2 = 0;
    vector<pair<int,int> >sortl,sortr;
    for (auto x : sorted){
        if (x.second-lpos<sz/2) sortl.push_back(x);
        else sortr.push_back(x);
    }
    vector<long long> ans;
    long long c1 = 0;
    for (auto x : sortr){
        while (c1<sortl.size() && sortl[c1]<x) c1++;
        inter2 += c1;
    }
    inter1 = ((long long)sortl.size()*(long long)(sortl.size()))-inter2;
   // printf("inter = %lld %lld\n",inter1,inter2);
   if (sortl.size()==1) return {inter1,inter2};
    vector<long long> r1 = allvals(lpos,sz/2,sortl);
    vector<long long> r2 = allvals(lpos+sz/2,sz/2,sortr);
    for (int x = 0; x<sz/2; x++){
        ans.push_back(r1[x]+r2[x]+inter1);
    }
    for (int x = 0; x<sz/2; x++){
        ans.push_back(r1[x]+r2[x]+inter2);
    }
    return ans;

}

inline void scan(int &a){
    a = 0;
    char ch = ' ';
    while (ch<'0' || ch>'9') ch = getchar();
    while (ch>='0' && ch<='9'){
        a = (a<<3)+(a<<1)+ch-'0';
        ch = getchar();
    }
}

set<pair<int,int> > vis;
vector<int> finpath;
int wantpos1 = -1;
int wantpos2 = -1;

bool dfs(int pos1, int pos2){
    int cur = vis.size();
    vis.insert({pos1,pos2});
    if (vis.size()>cur){
       // printf("vis %d %d\n",pos1,pos2);
        if (pos1==wantpos1 && pos2==wantpos2) return true;
        int t1 = pos1>=n/2?pos1-n/2:(pos1+n/2);
        int t2 = pos2>=n/2?pos2-n/2:(pos2+n/2);
        if (dfs(t1,t2)){
            finpath.push_back(1);
            return true;
        }
        t1 = (pos1&1)?(pos1/2+n/2):pos1/2;
        t2 = (pos2&1)?(pos2/2+n/2):pos2/2;
        if (dfs(t1,t2)){
            finpath.push_back(2);
            return true;
        }
    }
    return false;
}

int main(){
    //freopen("test.txt","r",stdin);
    scan(n);
    logn = n;
    n = 1<<n;
    if (n==1){
        printf("0\n");
        return 0;
    }
    vector<int> t;
    for(int x = 0; x<n; x++){
        scan(arr[x]);
        t.push_back(arr[x]);
    }
    vector<pair<int,int> > sorted;
    sorted.clear();
    for (int x = 0; x<n; x++){
        sorted.push_back({t[x],x});
    }
    sort(sorted.begin(),sorted.end());
    long long ans = 999999999999999999LL;
    int anspos;
    int numlogn;
    for (int x = 0; x<logn; x++){
        for (int x2 = 0; x2<n; x2++){
            curarr[x2] = t[x2];
        }
        auto res = allvals(0,n,sorted);
        int c = 0;
        for (auto x2 : res){
            //printf("%d ",x2);
            if (x2<ans){
                ans= x2;
                anspos = c;
                numlogn = x;
            }
            c++;
            //printf("%lld \n",x);
        }
        //printf("\n");
        t = f1(t);
        sorted.clear();
        for (int x2 = 0; x2<n; x2++){
            sorted.push_back({t[x2],x2});
        }
        sort(sorted.begin(),sorted.end());
    }
    for (int x = 0; x<numlogn; x++){
        t = f1(t);
    }
    for (int x = 0; x<n; x++){
        curarr[x] = t[x];
    }
    for (int x = 0; x<n; x++){
        if (curarr[x]==arr[0]) wantpos1 = x;
        if (curarr[x]==arr[1]) wantpos2 = x;
    }
   // printf("anspos = %d\n",anspos);
    for (int x = logn-1; x>=0; x--){
        if (anspos&(1<<x)){
            wantpos1 ^= (1<<x);
            wantpos2^=(1<<x);
        }
    }
   // printf("wantpos = %d %d\n",wantpos1,wantpos2);
    dfs(0,1);


    printf("%lld\n",ans);
    for (int x = finpath.size()-1; x>=0; x--){
        printf("%d",finpath[x]);
    }
}

Compilation message (stderr)

cheerleaders.cpp: In function 'std::vector<int> f1(std::vector<int>)':
cheerleaders.cpp:9:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
    9 |     for (int x = 0; x<v.size(); x+=2){
      |                     ~^~~~~~~~~
cheerleaders.cpp:12:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for (int x = 1; x<v.size(); x+=2){
      |                     ~^~~~~~~~~
cheerleaders.cpp: In function 'std::vector<long long int> allvals(int, int, std::vector<std::pair<int, int> >)':
cheerleaders.cpp:34:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   34 |         while (c1<sortl.size() && sortl[c1]<x) c1++;
      |                ~~^~~~~~~~~~~~~
cheerleaders.cpp: In function 'bool dfs(int, int)':
cheerleaders.cpp:70:19: warning: comparison of integer expressions of different signedness: 'std::set<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   70 |     if (vis.size()>cur){
      |         ~~~~~~~~~~^~~~
cheerleaders.cpp: In function 'int main()':
cheerleaders.cpp:136:22: warning: 'numlogn' may be used uninitialized in this function [-Wmaybe-uninitialized]
  136 |     for (int x = 0; x<numlogn; x++){
      |                     ~^~~~~~~~
cheerleaders.cpp:148:19: warning: 'anspos' may be used uninitialized in this function [-Wmaybe-uninitialized]
  148 |         if (anspos&(1<<x)){
      |             ~~~~~~^~~~~~~

• Subtask 1: 16 / 16
• Subtask 2: 10 / 10
• Subtask 3: 25 / 25
• Subtask 4: 21 / 21
• Subtask 5: 0 / 28