二分查找 BestCoder Round #42 1002 Gunner II

题目传送门

 /*
     题意：查询x的id，每次前排的树倒下
     使用lower_bound ()查找高度，f[i]记录第一棵高度为x树的位置，查询后+1(因为有序)
 */
 #include <cstdio>
 #include <algorithm>
 #include <cstring>
 using namespace std;

 const int MAXN = 1e5 + ;
 const int INF = 0x3f3f3f3f;
 struct A
 {
     int v, id;
     bool operator < (const A &x) const
     {
         if (v == x.v)    return id < x.id;
         return v < x.v;
     }
 }a[MAXN];
 int h[MAXN], f[MAXN];

 inline int read(void)
 {
     int x = , f = ;    char ch = getchar ();
     while (ch < '' || ch > '')    {if (ch == '-') f = -;    ch = getchar ();}
     while (ch >='' && ch <= '')    {x = x *  + ch - '';    ch = getchar ();}
     return f * x;
 }

 int main(void)        //HDOJ 5233 Gunner II
 {
     int n, q;
     while (scanf ("%d%d", &n, &q) == )
     {
         for (int i=; i<=n; ++i)    {a[i].v = read ();    a[i].id = i;}
         sort (a+, a++n);
         for (int i=; i<=n; ++i)
         {
             f[i] = i;    h[i] = a[i].v;
         }
         while (q--)
         {
             int x, p;    scanf ("%d", &x);
             p = lower_bound (h+, h++n, x) - h;
             if (h[f[p]] != x)    {puts ("-1");    continue;}
             printf ("%d\n", a[f[p]].id);
             f[p]++;
         }
     }

     return ;
 }

 /*
 5 5
 1 2 3 4 1
 1 3 1 4 2
 */