1381A1 - Prefix Flip (Easy Version.md‘

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whiteawll 2022-08-16 14:53:50 博主文章分类：练习题目 ©著作权

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// Problem: A1. Prefix Flip (Easy Version)
// Contest: Codeforces - Codeforces Round #658 (Div. 1)
// URL: https://codeforces.com/problemset/problem/1381/A1
// Memory Limit: 256 MB
// Time Limit: 1000 ms
// 2022-02-27 17:49:17
// 
// Powered by CP Editor (https://cpeditor.org)

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

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,l,r) for(int i=(l);i>=(r);i--)
#define ll long long
#define pii pair<int, int>
#define mset(s,t) memset(s,t,sizeof(t))
#define mcpy(s,t) memcpy(s,t,sizeof(t))
#define fi first
#define se second
#define pb push_back
#define all(x) (x).begin(),(x).end()
#define SZ(x) ((int)(x).size())
#define mp make_pair

const ll mod = 1e9 + 7;

inline ll qmi (ll a, ll b) {
    ll ans = 1;
    while (b) {
        if (b & 1) ans = ans * a%mod;
        a = a * a %mod;
        b >>= 1;
    }
    return ans;
}
inline int read () {
    int x = 0, f = 0;
    char ch = getchar();
    while (!isdigit(ch)) f |= (ch=='-'),ch= getchar();
    while (isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
    return f?-x:x;
}
template<typename T> void print(T x) {
    if (x < 0) putchar('-'), x = -x;
    if (x >= 10) print(x/10);
    putchar(x % 10 + '0');
}
inline ll sub (ll a, ll b) {
    return ((a - b ) %mod + mod) %mod;
}
inline ll add (ll a, ll b) {
    return (a + b) %mod;
}
inline ll inv (ll a) {
    return qmi(a, mod - 2);
}
vector<int> ans;
void solve() {
    ans.clear();
    int n;
    cin >> n;
    string a, b;
    cin >> a >> b;
    int i = n - 1, len = 0;
    
    for (int j =  n - 1; j >= 0; j --) {
        int i = j;
        while (i >= 0 && a[i] == b[i]) {
            i --;
        }
        if (i >= 0) {
        ans.pb(i + 1);
        ans.pb(1);
        ans.pb(i + 1);
        }
        j = i;
    }
    
    cout << ans.size() << " ";
    for (auto t : ans) cout << t << " ";
    puts("");
} 
int main () {
    int t;
    t =1;
    cin >> t;
    while (t --) solve();
    return 0;
}