先二分答案,然后从后往前贪心就行
/*************************************************************************
> File Name: hdu5248.cpp
> Author: ALex
> Mail: [email protected]
> Created Time: 2015年05月31日 星期日 10时46分06秒
************************************************************************/
#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <queue>
#include <stack>
#include <map>
#include <bitset>
#include <set>
#include <vector>
using namespace std;
const double pi = acos(-1.0);
const int inf = 0x3f3f3f3f;
const double eps = 1e-15;
typedef long long LL;
typedef pair <int, int> PLL;
static const int N = 100110;
int arr[N];
int main() {
int t, icase = 1;
scanf("%d", &t);
while (t--) {
int n;
scanf("%d", &n);
for (int i = 1; i <= n; ++i) {
scanf("%d", &arr[i]);
}
int l = 0, r = 1000000000;
int mid;
int ans = -1;
while (l <= r) {
mid = (l + r) >> 1;
bool flag = 1;
int last = arr[n] + mid;
for (int i = n - 1; i >= 1; --i) {
if (arr[i] + mid < last) {
last = arr[i] + mid;
}
else if (arr[i] - mid >= last) {
flag = 0;
break;
}
else {
--last;
}
}
if (flag) {
ans = mid;
r = mid - 1;
}
else {
l = mid + 1;
}
}
printf("Case #%d:\n", icase++);
printf("%d\n", ans);
}
return 0;
}
时间: 2024-11-05 22:53:03