The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1); so the first ten triangle numbers are:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
By converting each letter in a word to a number corresponding to its alphabetical position and adding these values we form a word value. For example, the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a triangle number then we shall call the word a triangle word.
Using words.txt (right click and 'Save Link/Target As...'), a 16K text file containing nearly two-thousand common English words, how many are triangle words?
题目大意：
三角形数序列中第 n 项的定义是： tn = ½n(n+1); 因此前十个三角形数是:
1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
通过将一个单词中每个字母在字母表中的位置值加起来，我们可以将一个单词转换为一个数。例如，单词SKY的值为19 + 11 + 25 = 55 = t10。如果单词的值是一个三角形数，我们称这个单词为三角形单词。
words.txt (右键另存为)是一个16K的文本文件，包含将近两千个常用英语单词。在这个文件中，一共有多少个三角形词？
//（Problem 42）Coded triangle numbers
// Completed on Tue, 19 Nov 2013, 03:34
// Language: C11
//
// 版权所有（C）acutus (mail: acutus@126.com)
// 博客地址：http://www.cnblogs.com/acutus/
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include <stdbool.h>
#include <math.h> bool test(int n)
{
int m;
m = (int)sqrt(n * );
if(m * (m + ) == * n) return true;
else return false;
} int count(char * s)
{
int i = ;
int sum = ;
while(s[i] != '\0') {
sum += s[i] - 'A' + ;
i++;
}
return sum;
} void solve(void)
{
FILE *fp;
int i, j, k;
char *s, c;
int sum = ;
char a[]; fp = fopen("words.txt", "r");
fseek(fp, , SEEK_END);
int file_size;
file_size = ftell(fp);
fseek(fp, , SEEK_SET);
s = (char*)malloc(file_size * sizeof(char));
fread(s, sizeof(char), file_size, fp); i = j = k = ;
while(i <= file_size) {
c = s[i++];
if(!isalpha(c)) {
if(c == ',') {
j = ;
if(test(count(a))) sum++;
memset(a,'\0', * sizeof(char));
}
} else {
a[j++] = c;
}
}
if(test(count(a))) sum++;
memset(a,'\0', * sizeof(char)); printf("%d\n",sum);
} int main(void)
{
solve();
return ;
}
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Answer:
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162 |