UVa OJ 1442 - Cav

Problem

Link: 1442 - Cav

Solution

Use greedy algorithm to deal with this problem.

Adjust the height of ceiling to fit the requirements.

Here is the code:

#include <iostream>#include <cstdio>using namespace std;const int maxn = 1e6+5;int cas, n, cnt;int ceiling[maxn], floor[maxn];int main() {    ios::sync_with_stdio(false);    cin.tie(0);    //freopen("input.txt" , "r", stdin );    //freopen("output.txt", "w", stdout);    cin >> cas;    while(cas--) {        cnt = 0;        cin >> n;        for (int i = 0; i < n; ++i) cin >> floor[i];        for (int i = 0; i < n; ++i) cin >> ceiling[i];        int tmp = maxn;        for (int i = 0; i < n; ++i) {            tmp = min(tmp, ceiling[i]);            tmp = max(tmp, floor[i]);            ceiling[i] = tmp;        }        tmp = maxn;        for (int i = n-1; i > -1; --i) {            tmp = min(tmp, ceiling[i]);            tmp = max(tmp, floor[i]);            ceiling[i] = tmp;            cnt += ceiling[i] - floor[i];        }        cout << cnt << '\n';    }    return 0;}