Getting a WA in DEVSTR

I was trying to solve this problem. I am getting a WA in all cases except case no. 2. My solution is like the one in the editorial. Here is a link to my submissions. Please help. Thanks.

Here’s my code:

#include <iostream>
#include <iomanip>

#include <cmath>
#include <string>

#include <algorithm>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <utility>
#include <vector>

using namespace std;

int main() {
    int t, n, k;
    string input;
    cin >> t;

    while(t--) {
        cin >> n >> k;
        cin.ignore();
        getline(cin, input);

        if (k == 1) {
            int z = 0, o = 0;
            for (int i = 0; i < n; i++) {
                if (i % 2) {
                    if (input[i] == '0') z++;
                    else if (input[i] == '1') o++;
                }
                else {
                    if (input[i] == '0') o++;
                    else if (input[i] == '1') z++;
                }
            }

            if (o > z) {
                cout << z << endl;
                for (int i = 0; i < n; i++) cout << static_cast<char>((i%2) + 48);
                cout << endl;
            }
            else {
                cout << o << endl;
                for (int i = 0; i < n; i++) cout << static_cast<char>(((i+1)%2) + 48);
                cout << endl;
            }
            continue;
        }

        int prev = 0;
        char c = input[0];
        int total = 0;

        for (int i = 1; i < n; i++) {
            if ((input[i] != c) || (i == n - 1)) {
                if (i == n - 1) i = n;
                total += floor(double(i - prev)/(k+1));

                int start = prev + k;
                if (((i - prev) % (k+1) == 0) && (i != n)) {
                    start--;
                }

                for (int j = start; j < i; j+=k+1) {
                    input[j] = static_cast<char>((c - 47) % 2 + 48);
                }

                prev = i;
                c = input[i];
            }
        }
        cout << total << endl;
        cout << input << endl;
    }

    return 0;
}

@dhruvsomani didn’t check your logic but your code outputs 2 for the following test case, although the correct answer is 1.

8 2

11111001

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Thanks. I’ll try to correct it.

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Thanks again. Got an AC.

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