Submission #70351

#	Time	Username	Problem	Language	Result	Execution time	Memory
70351		evpipis	The Big Prize (IOI17_prize)	C++11	90 / 100	112 ms	2144 KiB

prize

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

//#define TEST

#define fi first
#define se second
#define mp make_pair
#define pb push_back
typedef long long ll;
typedef pair<int, int> ii;

const int len = 2e5+5;
ii arr[len];
int pos, n, sum;

/*vector<int> ask(int i) {
    fprintf(fout, "A %d\n", i);
    fflush(fout);
    vector<int> result(2);
    if (fscanf(fin, "%d %d", &result[0], &result[1]) != 2) {
        cerr << "tester error" << endl;
        cerr << "could not read query response" << endl;
        exit(0);
    }
    if (result[0] < 0) {
        exit(0);
    }
    return result;
}*/

#ifdef TEST
vector<int> ask(int i){
    printf("ask %d\n", i), fflush(stdout);
    int a, b;
    scanf("%d %d", &a, &b);
    vector<int> temp;
    temp.pb(a), temp.pb(b);
    return temp;
}
#endif

ii val(int i){
    if (arr[i] != mp(-1, -1))
        return arr[i];

    vector<int> temp = ask(i);
    return arr[i] = mp(temp[0], temp[1]);
}

int bs(){
    int l = pos, r = n-1, ans;
    while (l <= r){
        int mid = (l+r)/2;
        if (val(mid) == val(pos)){
            ans = mid;
            l = mid+1;
        }
        else
            r = mid-1;
    }

    return ans;
}

int find_best(int N){
    n = N, sum = 0, pos = 0;
    for (int i = 0; i < n; i++)
        arr[i] = mp(-1, -1);

    for (int i = 0; i < min(500, n); i++)
        sum = max(sum, val(i).fi + val(i).se);

    while (pos < n){
        if (val(pos).fi+val(pos).se != sum){
            if (val(pos) == mp(0, 0))
                return pos;
            pos++;
        }
        else{
            pos = bs() + 1;
        }
    }

    return 0;
}

#ifdef TEST
int main(int argc, char **argv) {
    int n;
    scanf("%d", &n);
    printf("%d\n", find_best(n));
    return 0;
}
#endif

Compilation message (stderr)

prize.cpp: In function 'int bs()':
prize.cpp:64:12: warning: 'ans' may be used uninitialized in this function [-Wmaybe-uninitialized]
     return ans;
            ^~~

• Subtask 1: 20 / 20
• Subtask 2: 70 / 80