题解A139.组合的输出

****#include <iostream>
using namespace std;
const int MAX_N = 25;
int n, r, arr[MAX_N], k = 1;
bool visited[MAX_N];
void dfs(int idx) {
if (idx > r) {
for (int i = 1; i <= r; i++)
cout << " " << arr[i];
cout << endl;
return;
}
for (int i = 1; i <= n; i++) {
if (!visited[i] && arr[idx - 1] < i) {
visited[i] = true;
arr[idx] = i;
dfs(idx + 1);
visited[i] = false;
}
}
}
int main() {
cin >> n >> r;
dfs(1);
return 0;
}

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