UVA

题意:有n个影碟,标号为1~n,位置为0~n-1,每次取出一个影碟看完后,将其放在最前面(标号为0处),问每个影碟取出前,其位置之前有多少个影碟。

分析:

1、数组大小开为100000*2,后100000个位置放初始的n个影碟,每次看完一个影碟后,依次向前放在前100000个位置中。

2、将放置影碟处标记为1---add(x, 1),当影碟取出时,再add(x,-1)。

3、通过sum(x)-1可知当前位置之前有多少个影碟。

#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<cmath>
#include<iostream>
#include<sstream>
#include<iterator>
#include<algorithm>
#include<string>
#include<vector>
#include<set>
#include<map>
#include<stack>
#include<deque>
#include<queue>
#include<list>
#define lowbit(x) (x & (-x))
const double eps = 1e-8;
inline int dcmp(double a, double b){
    if(fabs(a - b) < eps) return 0;
    return a > b ? 1 : -1;
}
typedef long long LL;
typedef unsigned long long ULL;
const int INT_INF = 0x3f3f3f3f;
const int INT_M_INF = 0x7f7f7f7f;
const LL LL_INF = 0x3f3f3f3f3f3f3f3f;
const LL LL_M_INF = 0x7f7f7f7f7f7f7f7f;
const int dr[] = {0, 0, -1, 1, -1, -1, 1, 1};
const int dc[] = {-1, 1, 0, 0, -1, 1, -1, 1};
const int MOD = 1000;
const double pi = acos(-1.0);
const int MAXN = 200000 + 10;
const int MAXT = 10000 + 10;
using namespace std;
int a[MAXN];
int n, m;
int pos[MAXN];
int sum(int x){
    int ans = 0;
    for(int i = x; i >= 1; i -= lowbit(i)){
        ans += a[i];
    }
    return ans;
}
void add(int x, int value){
    for(int i = x; i < MAXN; i += lowbit(i)){
        a[i] += value;
    }
}
vector<int> ans;
int main(){
    int T;
    scanf("%d", &T);
    while(T--){
        ans.clear();
        memset(a, 0, sizeof a);
        scanf("%d%d", &n, &m);
        for(int i = 1; i <= n; ++i){
            pos[i] = 100000 + i;
            add(pos[i], 1);
        }
        int cnt = 100000;
        while(m--){
            int k;
            scanf("%d", &k);
            ans.push_back(sum(pos[k]) - 1);
            add(pos[k], -1);
            pos[k] = cnt--;
            add(pos[k], 1);
        }
        int len = ans.size();
        for(int i = 0; i < len; ++i){
            if(i) printf(" ");
            printf("%d", ans[i]);
        }
        printf("
");
    }
    return 0;
}

  

原文地址:https://www.cnblogs.com/tyty-Somnuspoppy/p/7389476.html