POJ

Farmer John and Betsy are playing a game with N (1 <= N <= 30,000)identical cubes labeled 1 through N. They start with N stacks, each containing a single cube. Farmer John asks Betsy to perform P (1<= P <= 100,000) operation. There are two types of operations:
moves and counts.
* In a move operation, Farmer John asks Bessie to move the stack containing cube X on top of the stack containing cube Y.
* In a count operation, Farmer John asks Bessie to count the number of cubes on the stack with cube X that are under the cube X and report that value.

Write a program that can verify the results of the game.
Input
* Line 1: A single integer, P

• Lines 2..P+1: Each of these lines describes a legal operation. Line 2 describes the first operation, etc. Each line begins with a ‘M’ for a move operation or a ‘C’ for a count operation. For move operations, the line also contains two integers: X and Y.For count operations, the line also contains a single integer: X.

Note that the value for N does not appear in the input file. No move operation will request a move a stack onto itself.
Output
Print the output from each of the count operations in the same order as the input file.
Sample Input
6
M 1 6
C 1
M 2 4
M 2 6
C 3
C 4
Sample Output
1
0
2

题解

感觉这个题还不错，做法可以参考 食物链

#include<cstdio>#include<cstring>#include<cmath>#include<queue>#include<stack>#include<vector>#include<algorithm>#include<map>using namespace std;#define INF 0x3f3f3f3fconst int MAX_N=1e5+5;int par[MAX_N],cnt[MAX_N];int hig[MAX_N];void init(){    for(int i=0;i<MAX_N;i++){        par[i]=i;        cnt[i]=0;        hig[i]=1;    }}int find(int x){    if(x==par[x]) return x;    int t=find(par[x]);    cnt[x]+=cnt[par[x]];    return par[x]=t;}void unite(int x,int y){    int fx=find(x);    int fy=find(y);    par[fx]=fy;    cnt[fx]=hig[fy];    hig[fy]+=hig[fx];    hig[fx]=0;    return ;}int main(){    init();    int n;    scanf("%d",&n);    while(n--){        char op;int x,y;        getchar();        scanf("%c%d",&op,&x);        if(op=='M'){            scanf("%d",&y);            unite(x,y);        }else{            find(x);            printf("%d\n",cnt[x]);        }    }    return 0;}