sdut 2411:Pixel density（第三届山东省省赛原题，字符串处理）
Pixel density
Time Limit: 1000ms Memory limit: 65536K 有疑问？点这里^_^
题目描述
Pixels per inch (PPI) or pixel density is a measurement of the resolution of devices in various contexts; typically computer displays, image scanners, and digital camera image sensors. Note, the unit is not square inches. Good quality photographs usually require 300 pixels per inch when printed. When the PPI is more than 300(phone), we call it retina screen. Sunnypiggy like the retina screen very much.
But you know it is expensive for Sunnypiggy and Sunnypiggy’s own smart phone
isn’t like that.
I tell you how to calculate the PPI. First we must know how
big the mobile phone’s screen is. Then we get the resolution (Hp*Wp) about it.
After that we calculate the diagonal resolution in pixels (Dp) and divided by
diagonal size in inches. Now you get the answer.
Maybe you knew it, but
Sunnypiggy’s math is very bad and he wants you to help him to calculate the
pixel density of all the electronic products he dreamed.
输入
First you will get an integer T which means the number of test cases, and then Sunnypiggy will tell you the name and type of the electronic products. And you know, Sunnypiggy is a careless boy and some data aren’t standard, just like 04.00 inches or 0800*0480.
输出
Output the answers to Sunnypiggy just like the sample output. Maybe it is not a phone. Sunnypiggy like such a form, although it seems no use. The result should be rounded to 2 decimal places. When it has no screen (0.0 inches) that we define the answer is 0.00(PPI).
示例输入
2 iPhone 4S 3.5 inches 960*640 PHONE The new iPad 0009.7 inches 2048*1536 PAD
示例输出
Case 1: The phone of iPhone 4S‘s PPI is 329.65. Case 2: The pad of The new iPad‘s PPI is 263.92.
提示
Wp is width resolution in pixels, Hp is height resolution in pixels.
来源
1 #include <iostream>
2 #include <string.h>
3 #include <cmath>
4 #include <stdio.h>
5 using namespace std;
6 char str[1000000];
7 double Abs(double n)
8 {
9 return n<0?-n:n;
10 }
11 void GetVal(char name[],char kind[],double &ppi)
12 {
13 //iPhone 4S 3.5 inches 960*640 PHONE
14 int len = strlen(str),indexl,indexr,i,t,x;
15 double a,b,c;
16 //类型后界
17 for(indexr=len-1;indexr>=0;indexr--)
18 if(str[indexr]!=‘ ‘)
19 break;
20 //类型前界
21 for(indexl=indexr;indexl>=0;indexl--)
22 if(str[indexl]==‘ ‘)
23 break;
24 //提取类型
25 t = 0;
26 for(i=indexl+1;i<=indexr;i++){
27 if(‘A‘<=str[i] && str[i]<=‘Z‘) //类型的大写全部转换成小写
28 kind[t++] = str[i] + 32;
29 else
30 kind[t++] = str[i];
31 }
32 kind[t] = ‘\0‘;
33 //a*b的b的后界
34 for(indexr = indexl;indexr>=0;indexr--)
35 if(str[indexr]!=‘ ‘)
36 break;
37 //提取b
38 t = 0;x = 1;
39 for(i=indexr;str[i]!=‘*‘;i--){
40 int tt = str[i]-‘0‘;
41 t = tt*x + t;
42 x*=10;
43 }
44 b = t;
45 //提取a
46 indexr = i-1;
47 t = 0;x = 1;
48 for(i=indexr;str[i]!=‘ ‘;i--){
49 int tt = str[i]-‘0‘;
50 t = tt*x + t;
51 x*=10;
52 }
53 a = t;
54 for(indexr = i;str[indexr]==‘ ‘;indexr--);
55 for(;str[indexr]!=‘ ‘;indexr--);
56 //找c的下界
57 for(;str[indexr]==‘ ‘;indexr--);
58 //找c的上界
59 for(indexl = indexr;str[indexl]!=‘ ‘;indexl--);
60 for(i = indexl+1;str[i]!=‘.‘ && i<=indexr;i++); //找到小数点或者到下界
61 if(str[i]==‘.‘){ //有小数点，证明是小数
62 //提取c的小数部分
63 c = 0;
64 double xx = 0.1;
65 int j;
66 for(j=i+1;str[j]!=‘ ‘;j++){
67 int tt = str[j]-‘0‘;
68 c = c+tt*xx;
69 xx/=10;
70 }
71 //提取c的整数部分
72 x = 1;
73 for(j=i-1;str[j]!=‘ ‘;j--){
74 int tt = str[j]-‘0‘;
75 c = c+tt*x;
76 x*=10;
77 }
78 indexr = j;
79 }
80 else { //不是小数点，证明是整数
81 //提取整数
82 c = 0;
83 x = 1;
84 int j;
85 for(j=indexr;str[j]!=‘ ‘;j--){
86 int tt = str[j]-‘0‘;
87 c = c+tt*x;
88 x*=10;
89 }
90 indexr = j;
91 }
92 //可以计算ppi了
93 if( Abs(c)<1e-9 ) //是0
94 ppi = 0;
95 else
96 ppi = sqrt(a*a+b*b)/c;
97 //名字后界
98 for(;indexr>=0;indexr--)
99 if(str[indexr]!=‘ ‘)
100 break;
101 //类型前界
102 for(indexl=0;str[indexl]==‘ ‘;indexl++);
103 //提取名字
104 t = 0;
105 for(i=indexl;i<=indexr;i++)
106 name[t++] = str[i];
107 name[t] = ‘\0‘;
108 }
109 int main()
110 {
111 int T;
112 cin>>T;
113 getchar();
114 for(int cnt = 1;cnt<=T;cnt++){
115 cin.getline(str,100000000,‘\n‘);
116 char name[10000],kind[10000];
117 double ppi;
118 GetVal(name,kind,ppi); //提取数据：名字，类型，ppi
119 printf("Case %d: The %s of %s‘s PPI is %.2lf.\n",cnt,kind,name,ppi);
120 }
121 return 0;
122 }
Freecode : www.cnblogs.com/yym2013