【BestCoder】 HDOJ 5233 Gunner II

#include <iostream>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <bitset>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <climits>
#include <cstdlib>
#include <cmath>
#include <time.h>
#define maxn 100005
#define maxm 40005
#define eps 1e-12
#define mod 998244353
#define INF 0x3f3f3f3f
#define PI (acos(-1.0))
#define lowbit(x) (x&(-x))
#define mp make_pair
#define ls o<<1
#define rs o<<1 | 1
#define lson o<<1, L, mid
#define rson o<<1 | 1, mid+1, R
#pragma comment(linker, "/STACK:102400000,102400000")
#define pii pair<int, int>
typedef long long LL;
typedef unsigned long long ULL;
//typedef int LL;
using namespace std;
LL qpow(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base;base=base*base;b/=2;}return res;}
LL powmod(LL a, LL b){LL res=1,base=a;while(b){if(b%2)res=res*base%mod;base=base*base%mod;b/=2;}return res;}
// head

int nxt[maxn << 1];
int val[maxn << 1];
int h[maxn << 1];
int x[maxn << 1];
int a[maxn];
int b[maxn];
int n, m;

void work()
{
int cnt = 0;
for(int i = 1; i <= n; i++) scanf("%d", &a[i]), x[cnt++] = a[i];
for(int i = 1; i <= m; i++) scanf("%d", &b[i]), x[cnt++] = b[i];

sort(x, x+cnt);
cnt = unique(x, x+cnt) - x;

for(int i = 1; i <= n; i++) a[i] = lower_bound(x, x+cnt, a[i]) - x;
for(int i = 1; i <= m; i++) b[i] = lower_bound(x, x+cnt, b[i]) - x;

cnt = 0;
memset(h, -1, sizeof h);
for(int i = n; i >= 1; i--) {
val[cnt] = i;
nxt[cnt] = h[a[i]];
h[a[i]] = cnt++;
}

for(int i = 1; i <= m; i++) {
int& e = h[b[i]];
if(~e) {
printf("%d\n", val[e]);
e = nxt[e];
}
else printf("-1\n");
}
}

int main()
{
while(scanf("%d%d", &n, &m)!=EOF) {
work();
}

return 0;
}