Educational Codeforces Round 73

1334 (-2), pupil
Rank: 2668

（虽然比上次好，但是摆脱不了掉分的命运。。。）

D. Make The Fence Great Again

http://codeforces.com/contest/1221/problem/D

分析：对每个高度来说，最多升高两次，因此可以对这个进行dp（一开始读错题了，没有看到是相邻不能同高，一开始以为所有都不能同高）

代码：

#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e6;
typedef long long ll;
const ll inf = 0x3f3f3f3f3f3f3f3f;
int n;
int h[maxn], w[maxn];
ll dp[maxn][3];

int main()
{
    int T; cin >> T;
    while (T--)
    {
        int n; cin >> n;
        for (int i = 1; i <= n; i++)
            scanf("%d%d", h + i, w + i);
        for (int i = 1; i <= n; i++)
            dp[i][0] = dp[i][1] = dp[i][2] = inf;
        dp[1][0] = 0, dp[1][1] = w[1], dp[1][2] = 2 * w[1];
        for (int i = 2; i <= n; i++)
        {
            for (int j = 0; j <= 2; j++)
                for (int k = 0; k <= 2; k++)
                    if (h[i - 1] + j != h[i] + k)
                        dp[i][k] = min(dp[i][k], w[i] * k + dp[i - 1][j]);
        }
        cout << min(dp[n][0], min(dp[n][1], dp[n][2])) << endl;
    }
}