Submission #562538

#	Time	Username	Problem	Language	Result	Execution time	Memory
562538		Iwanttobreakfree	Finding Routers (IOI20_routers)	C++17	100 / 100	11 ms	708 KiB

routers

#include "routers.h"
#include <vector>
using namespace std;
vector<int> guarda(100001,-1);
vector<int> find_routers(int lon, int n, int q) {
    vector<int> ans(n);
    vector<int> maxinum(n);
    for(int i=0;i<n;i++)maxinum[i]=0;
    vector<int> mininum(n);
    for(int i=0;i<n;i++)mininum[i]=lon;
    ans[0]=guarda[0]=guarda[1]=0;
    int l=0,r;
    for(int i=1;i<n;i++){
    l=maxinum[i-1];
    r=mininum[i];
    int sol;
    while(l<=r){
    	int mid=(l+r)/2,cerc;
    	if(guarda[mid]==-1){
            guarda[mid]=use_detector(mid);
            //if(mid&1)guarda[mid-1]=guarda[mid];
    	}
    	cerc=guarda[mid];
    	if(cerc<i){
    		l=mid+1;
    		sol=mid;
		}
		else r=mid-1;
		if(maxinum[cerc]<mid)maxinum[cerc]=mid;
		if(mininum[cerc]>mid)mininum[cerc]=mid;
		for(int j=0;j<cerc;j++)
                mininum[j]=min(mid+(j-guarda[mid])*2,mininum[j]);
        for(int j=cerc;j<n;j++)
                maxinum[j]=max(maxinum[j],mid+(j-guarda[mid])*2);
	}
	ans[i]=2*sol-ans[i-1];
	}
	return ans;
}

Compilation message (stderr)

routers.cpp: In function 'std::vector<int> find_routers(int, int, int)':
routers.cpp:36:10: warning: 'sol' may be used uninitialized in this function [-Wmaybe-uninitialized]
   36 |  ans[i]=2*sol-ans[i-1];
      |         ~^~~~

• Subtask 1: 16 / 16
• Subtask 2: 21 / 21
• Subtask 3: 23 / 23
• Subtask 4: 40 / 40