#include "bits/stdc++.h"
#define int long long
using namespace std;
mt19937_64 rng((int) std::chrono::steady_clock::now().time_since_epoch().count());
int rnd(int x, int y) {
return uniform_int_distribution<int>(x, y)(rng);
}
const int MAXN = 1e6 + 10;
string a, b;
int n;
int ps[MAXN];
int zero(int l, int r) {
int nums = ps[r] - ps[l];
int cnt0, cnt1;
if(nums % 2 == 1) {
cnt0 = cnt1 = (nums + 1) / 2;
}
else {
cnt0 = nums / 2 + 1, cnt1 = nums / 2;
if(b[l] == '1') swap(cnt0, cnt1);
}
return cnt0;
}
int one(int l, int r) {
int nums = ps[r] - ps[l];
int cnt0, cnt1;
if(nums % 2 == 1) {
cnt0 = cnt1 = (nums + 1) / 2;
}
else {
cnt0 = nums / 2 + 1, cnt1 = nums / 2;
if(b[l] == '1') swap(cnt0, cnt1);
}
return cnt1;
}
int mincnt(int l, int r) {
return min(zero(l, r), one(l, r));
}
void solve(int tc) {
cin >> n;
cin >> a >> b;
a = " " + a;
b = " " + b;
for(int i=2; i<=n; i++) ps[i] = ps[i-1] + (b[i] != b[i-1]);
int dp[n+1];
dp[0] = 0;
for(int i=1; i<=n; i++) {
int cnteq = 0, cntneq = 0;
dp[i] = 1e9;
for(int j=i-1; j>=0; j--) {
cnteq += (a[j+1] == b[j+1]);
cntneq += (a[j+1] != b[j+1]);
if(cntneq == 0) {
dp[i] = min(dp[i], dp[j]);
}
if(cnteq == 0) {
dp[i] = min(dp[i], dp[j] + 1);
}
dp[i] = min(dp[i], dp[j] + 1 + mincnt(l, r));
}
}
}
int32_t main() {
ios::sync_with_stdio(0);
cin.tie(0);
int t = 1;
// cin >> t;
for(int i=1; i<=t; i++) solve(i);
}
/*
g++ T2421.cpp -std=c++17 -O2 -o T2421
./T2421 < input.txt
*/
Compilation message
lamp.cpp: In function 'void solve(long long int)':
lamp.cpp:59:45: error: 'l' was not declared in this scope
59 | dp[i] = min(dp[i], dp[j] + 1 + mincnt(l, r));
| ^
lamp.cpp:59:48: error: 'r' was not declared in this scope
59 | dp[i] = min(dp[i], dp[j] + 1 + mincnt(l, r));
| ^
