题目传送门
1 /*
2 水题：判断前后的差值是否为1，b[i]记录差值，若没有找到，则是第一个出错
3 */
4 #include <cstdio>
5 #include <iostream>
6 #include <algorithm>
7 #include <cstring>
8 #include <string>
9 #include <cmath>
10 using namespace std;
11
12 const int MAXN = 1e5 + 10;
13 const int INF = 0x3f3f3f3f;
14 int a[MAXN];
15 int b[MAXN];
16
17 int main(void) //HDOJ 4727 The Number Off of FFF
18 {
19 //freopen ("L.in", "r", stdin);
20
21 int t, cas = 0;
22 int n;
23 scanf ("%d", &t);
24 while (t--)
25 {
26 scanf ("%d", &n);
27
28 a[0] = b[0] = 0;
29 for (int i=1; i<=n; ++i)
30 {
31 scanf ("%d", &a[i]);
32 b[i] = a[i] - a[i-1];
33 }
34
35 int ans = -1;
36 for (int i=2; i<=n; ++i)
37 {
38 if (b[i] != 1)
39 {
40 ans = i; break;
41 }
42 }
43 if (ans == -1) ans = 1;
44
45 printf ("Case #%d: %d
", ++cas, ans);
46 }
47
48 return 0;
49 }
50
51 /*
52 Case #1: 3
53 Case #2: 3
54 */