HDU 5037 Frog（北京网络赛F题）

HDU Frog

题目链接

思路：贪心搞，记录青蛙当前和上一次的位置，如果遇到一个区间跳不过去，要加石头，就按两步长度为(l + 1)去放会使得步数最大，注意边界条件有可能一步就能跳过去

代码：

#include <cstdio>#include <cstring>#include <algorithm>using namespace std;const int N = 200005;int t, n, m, l;int r[N];int solve() {int ans = 0;int now = 0;int pre = -l;int st = 0;while (now < m) {if (now + l < r[st]) {int tmp = now - pre;int len = r[st] - now;int ci = len / (l + 1) - 1;ans += ci * 2;now += ci * (l + 1);pre = now - tmp;ans++;pre = now;now += (1 + l) - tmp;} else {while (now + l >= r[st] && st <= n)st++;pre = now;now = r[st - 1];ans++;}}return ans;}int main() {int cas = 0;scanf("%d", &t);while (t--) {scanf("%d%d%d", &n, &m, &l);for (int i = 0; i < n; i++)scanf("%d", &r[i]);sort(r, r + n);r[n] = m;printf("Case #%d: %d\n", ++cas, solve());}return 0;}