Submission #905459

#	Time	Username	Problem	Language	Result	Execution time	Memory
905459		nightfal	The Big Prize (IOI17_prize)	C++14	0 / 100	4 ms	436 KiB

prize

//#include "prize.h"
#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

static const int max_q = 10000;
static int n;
static int query_count = 0;
static vector<int> g;
static vector<vector<int> > rank_count;

int find_best(int n);
std::vector<int> ask(int i);

int subtask1(int n){
    int start=0, end=n-1;
    while (start<end) {
        int mid = (start+end)/2;
        vector<int> ans = ask(mid);
        if (!ans[0] && !ans[1]) return mid;
        else if (!ans[0]) start=mid+1;
        else end = mid-1;
    }
    return start;
}

int bSearch(int start, int end, std::vector<int> sAns, std::vector<int> eAns, int maxVal) {
    int result;
    if (eAns[0]==sAns[0]) return -1;
    int mid = (start+end+1)/2;
    vector<int> mAns = ask(mid);
    if (mAns[0]+mAns[1]==0) return mid;
    int midL=mid, midR=mid;
    if(mAns[0]+mAns[1]<maxVal) {midL = start, midR = end;}

    for(int i=mid-1; i>start; i--) {
        mAns = ask(i);
        if(mAns[0]+mAns[1]==0) return i;
        if(mAns[0]+mAns[1]==maxVal) {midL=i; break;}
    }
    result = bSearch(start,midL,sAns,mAns,maxVal);
    if (result != -1) return result;

    for(int i=mid+1; i<end; i++) {
        mAns = ask(i);
        if(mAns[0]+mAns[1]==0) return i;
        if(mAns[0]+mAns[1]==maxVal) {midR=i; break;}
    }
    return bSearch(midR,end,mAns,eAns,maxVal);
}

int find_best(int n) {
    // return subtask1(n);
    int m = min(500,n), maxVal=0, maxIdx=-1;
    vector<int> ans;
	for(int i = 0; i < m; i++) {
        ans = ask(i);
        if (maxVal<ans[0]+ans[1]) {maxVal=ans[0]+ans[1]; maxIdx=i;}
    }
	return bSearch(0,n-1,ask(0),ask(n-1),maxVal);
}

Compilation message (stderr)

prize.cpp: In function 'int find_best(int)':
prize.cpp:56:35: warning: variable 'maxIdx' set but not used [-Wunused-but-set-variable]
   56 |     int m = min(500,n), maxVal=0, maxIdx=-1;
      |                                   ^~~~~~
prize.cpp: At global scope:
prize.cpp:10:12: warning: 'query_count' defined but not used [-Wunused-variable]
   10 | static int query_count = 0;
      |            ^~~~~~~~~~~
prize.cpp:9:12: warning: 'n' defined but not used [-Wunused-variable]
    9 | static int n;
      |            ^

• Subtask 1: 0 / 20
• Subtask 2: 0 / 80