158A - Next Round.cpp

/*
"Contestant who earns a score equal to or greater than the k-th place finisher's score will advance to the next round, as long as the contestant earns a positive score..." — an excerpt from contest rules.

A total of n participants took part in the contest (n?=?k), and you already know their scores. Calculate how many participants will advance to the next round.

Input
The first line of the input contains two integers n and k (1?=?k?=?n?=?50) separated by a single space.

The second line contains n space-separated integers a1,?a2,?...,?an (0?=?ai?=?100), where ai is the score earned by the participant who got the i-th place. The given sequence is non-increasing (that is, for all i from 1 to n?-?1 the following condition is fulfilled: ai?=?ai?+?1).

Output
Output the number of participants who advance to the next round.

Examples
inputCopy
8 5
10 9 8 7 7 7 5 5
outputCopy
6
inputCopy
4 2
0 0 0 0
outputCopy
0
Note
In the first example the participant on the 5th place earned 7 points. As the participant on the 6th place also earned 7 points, there are 6 advancers.

In the second example nobody got a positive score.
*/


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

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    
    int n, k;
    cin >> n >> k;
    
    vector <int> v(n);
    
    for (int i = 0; i < n; i++) cin >> v[i];
    
    int kval = v[k - 1];
    
    int res;
    
    for (res = k; res < n; res++) {
    	if (v[res] != kval)
    		break;
	}
	
	if (kval <= 0) {
		for (res = k - 1; res >= 0; res--) {
			if (v[res] > 0) break;
		}
		res += 1;
	}

	res = res <= 0 ? 0 : res;
	
	cout << res;

    return 0;
}