POJ训练计划2418

解题报告

Tire树。

#include <iostream> #include <cstring> #include <cstdio> #include <algorithm> using namespace std; struct node { int v; node *next[256]; }; int cnt=0,q; char ch[100],str1[100]; node *newnode() { node *p=new node; p->v=0; for(int i=0; i<256; i++) p->next[i]=NULL; return p; } void add(node *root,char *str) { node *p=root; int n=strlen(str); for(int i=0; i<n; i++) { int t=str[i]; if(p->next[t]==NULL) { p->next[t]=newnode(); } p=p->next[t]; } p->v++; } int fine(node *root,char *str) { node *p=root; int n=strlen(str); for(int i=0; i<n; i++) { int t=str[i]; if(p->next[t]==NULL) return 0; p=p->next[t]; } return p->v; } void dfs(node *p) { if(p->v) { ch[q]=0; printf("%s %.4lf\n",ch,(100.0*p->v)/cnt); } for(int i=0; i<256; i++) { if(p->next[i]) { ch[q++]=i; dfs(p->next[i]); q--; } } } int main() { node *root=newnode(); //freopen("1","r",stdin); q=0;cnt=0; while(fgets(str1,100,stdin)!=NULL) { cnt++; int l=strlen(str1); str1[l-1]=0; add(root,str1); } dfs(root); return 0; } Hardwood Species Time Limit: 10000MS Memory Limit: 65536KTotal Submissions: 18140 Accepted: 7190

Description

Hardwoods are the botanical group of trees that have broad leaves, produce a fruit or nut, and generally go dormant in the winter.  America's temperate climates produce forests with hundreds of hardwood species -- trees that share certain biological characteristics. Although oak, maple and cherry all are types of hardwood trees, for example, they are different species. Together, all the hardwood species represent 40 percent of the trees in the United States.  On the other hand, softwoods, or conifers, from the Latin word meaning "cone-bearing," have needles. Widely available US softwoods include cedar, fir, hemlock, pine, redwood, spruce and cypress. In a home, the softwoods are used primarily as structural lumber such as 2x4s and 2x6s, with some limited decorative applications.  Using satellite imaging technology, the Department of Natural Resources has compiled an inventory of every tree standing on a particular day. You are to compute the total fraction of the tree population represented by each species.

Input

Input to your program consists of a list of the species of every tree observed by the satellite; one tree per line. No species name exceeds 30 characters. There are no more than 10,000 species and no more than 1,000,000 trees.

Output

Print the name of each species represented in the population, in alphabetical order, followed by the percentage of the population it represents, to 4 decimal places.

Sample Input

Red Alder Ash Aspen Basswood Ash Beech Yellow Birch Ash Cherry Cottonwood Ash Cypress Red Elm Gum Hackberry White Oak Hickory Pecan Hard Maple White Oak Soft Maple Red Oak Red Oak White Oak Poplan Sassafras Sycamore Black Walnut Willow

Sample Output

Ash 13.7931 Aspen 3.4483 Basswood 3.4483 Beech 3.4483 Black Walnut 3.4483 Cherry 3.4483 Cottonwood 3.4483 Cypress 3.4483 Gum 3.4483 Hackberry 3.4483 Hard Maple 3.4483 Hickory 3.4483 Pecan 3.4483 Poplan 3.4483 Red Alder 3.4483 Red Elm 3.4483 Red Oak 6.8966 Sassafras 3.4483 Soft Maple 3.4483 Sycamore 3.4483 White Oak 10.3448 Willow 3.4483 Yellow Birch 3.4483

Hint

This problem has huge input, use scanf instead of cin to avoid time limit exceeded.

转载于:https://www.cnblogs.com/bhlsheji/p/5086459.html

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