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看了网上的一些介绍线段树的文档,不得要领,有没有大侠推荐下适合初学者的?找给定数组的任意长度子数组的最大值(Priority) 用赢者树的结构实现 也能过,就是慢点 详细见下: /* Title : RMQ(Range Minimum Query)问题的Binary Tree解法, 查询一指定数列任意一段区间内最(大)元素的位置 Time Complex : O(n) 预处理, O(logn) 每次查询 Space Complex : O(3*n) Total space Author : song Date : 9.3.2005 */ #include <cstdio> const int MAX = 1<<16; //MAX is a power of 2 and just bigger than n int key[MAX]; //数列 int n; //数列长度 int pp[MAX*2]; //binary tree数组,pp[i]保存i子树覆盖的区间里最值的序号 inline bool RMQcmp(int i, int j) //比较函数 { //like a heap, here we us > to get a Minimum Result, //and < to get a Maximum one return key[i] > key[j]; } void RMQCreate() //预处理,建树 { int f = MAX, t = MAX + n - 1, i; for(i = 0; i < n; ++i) pp[i+MAX] = i; for( ;f < t; f /= 2, t /= 2) { for(i = f; i < t ; i+= 2) { if( !RMQcmp(pp[i], pp[i+1]) ) pp[i/2] = pp[i]; else pp[i/2] = pp[i+1]; } if(!(t&1)) pp[t/2] = pp[t]; } } int RMQFind(int ss, int ee) //返回原数列key[ss - ee]之间最小元素的序号 { int k, f, t; ss += MAX, ee += MAX; k = !RMQcmp(pp[ss] ,pp[ee]) ? pp[ss] : pp[ee]; for( f = ss, t = ee; f < t; f/=2, t/=2) { if( !(f&1) && f + 1 < t && !RMQcmp(pp[f+1], k)) k = pp[f+1]; if( (t&1) && t - 1 > f && !RMQcmp(pp[t-1], k)) k = pp[t-1]; } return k; } int main() { /* main()里做的事: 1.先初始化好key数列,及比较函数RMQcmp()。key[]的名字可改,只要cmp对应上就行。 2.调用RMQCreate()预处理 3.查询key[0,n-1]之间最小元素的序号,只需调用RMQFind(0, n-1) */ return 0; } Followed by:
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