题目链接：http://acm.hnu.cn/online/?action=problem&type=show&id=12812
一直弄错了一个题意，教训啊，比赛最怕的就是弄错题意了
1 #include<cstdio> 2 #include<iostream> 3 #include<algorithm> 4 #include<cstring> 5 #include<cmath> 6 #include<cstdlib> 7 using namespace std; 8 const int maxn = 1000+5; 9 int num[maxn],X[maxn],flag[maxn]; 10 11 int main() 12 { 13 // freopen("A2.out","w",stdout); 14 // freopen("A.in","r",stdin); 15 int n; 16 char str[30]; 17 while(scanf("%d",&n),n) 18 { 19 memset(flag,0,sizeof(flag)); 20 int num_x = 0,end = 0; 21 for(int i = 1;i <= n;++i) 22 { 23 scanf("%s",str); 24 if(str[0] == 'X' || str[0] == 'x') 25 { 26 flag[i] = 1; 27 X[num_x++] = i; 28 } 29 else num[i] = atoi(str); 30 if(i > 1 && flag[i] == 1 && flag[i-1] == 1) 31 end = 1; 32 } 33 if(num_x >= n || end) /////全是x无法判断,超过两个x在一起也是无解 34 { 35 printf("none "); 36 continue; 37 } 38 for(int i = 1;i < n;++i) 39 if(flag[i] == 0 && flag[i+1] == 0) 40 { 41 if(((i & 1) && num[i] >= num[i+1]) || (!(i & 1) && num[i] <= num[i+1])) 42 { 43 end = 1; 44 break; 45 } 46 } 47 if(end) /////出现不符合规则的情况 48 { 49 printf("none "); 50 continue; 51 } 52 int l = -0x7fffffff,r = 0x7fffffff; 53 for(int i = 0;i < num_x;++i) 54 if(X[i] & 1) 55 { 56 if(X[i] > 1 && flag[X[i]-1] == 0) 57 r = min(r,num[X[i]-1] - 1); 58 if(X[i] < n && flag[X[i]-1] == 0) 59 r = min(r,num[X[i]+1] - 1); 60 } 61 else 62 { 63 if(X[i] > 1 && flag[X[i]-1] == 0) 64 l = max(l,num[X[i]-1] + 1); 65 if(X[i] < n && flag[X[i]+1] == 0) 66 l = max(l,num[X[i]+1] + 1); 67 } 68 if(l == r) 69 printf("%d ",l); 70 else if(l > r) 71 printf("none "); 72 else printf("ambiguous "); 73 } 74 return 0; 75 }