Submission #427999

#	Time	Username	Problem	Language	Result	Execution time	Memory
427999		tengiz05	Lamps (JOI19_lamps)	C++17	4 / 100	17 ms	31620 KiB

lamp

#include <bits/stdc++.h>
int dp[2000][2000][2];
int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);
    int n;
    std::cin >> n;
    if (n > 500) {
        std::string a, b;
        std::cin >> a >> b;
        int ans = 0;
        for (int i = 0; i < n; i++) {
            if (b[i] != '1') {
                continue;
            }
            while (i + 1 < n && b[i + 1] == '1') {
                i++;
            }
            ans++;
        }
        std::cout << ans << "\n";
    } else {
        std::string a[2], b;
        std::cin >> a[0] >> b;
        a[1] = a[0];
        for (int i = 0; i < n; i++) {
            a[1][i] ^= 1;
        }
        auto cost = [&](char c, int l, int r) {
            int ans = 0;
            for (int i = l; i <= r; i++) {
                if (c != b[i]) {
                    while (i + 1 <= r && b[i + 1] != c) {
                        i++;
                    }
                    ans++;
                }
            }
            return ans;
        };
        memset(dp, -1, sizeof dp);
        std::function<int(int, int, int)> calc = [&](int l, int r, int f) {
            if (l == r) {
                return int(a[f][l] != b[l]);
            }
            int &ret = dp[l][r][f];
            if (~ret) {
                return ret;
            }
            ret = 1e9;
            ret = std::min(ret, calc(l, r, f ^ 1) + 1);
            ret = std::min(ret, cost('0', l, r) + 1);
            ret = std::min(ret, cost('1', l, r) + 1);
            for (int i = l; i < r; i++) {
                ret = std::min(ret, calc(l, i, f) + calc(i + 1, r, f));
            }
            return ret;
        };
        std::cout << calc(0, n - 1, 0) << "\n";
    }
    return 0;
}

• Subtask 1: 0 / 6
• Subtask 2: 0 / 41
• Subtask 3: 4 / 4
• Subtask 4: 0 / 49