poj3218

模拟，注意Justify模式的最后一行，无论有几个单词都要用Left方式输出。

#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <cstring>
using namespace std;

#define maxn 505
#define maxl 80
#define max_len 75

char word[maxn][maxl];
char cmd[3];
int n;
int sum[maxn];
int word_len[maxn];

void input()
{
    scanf("%s", cmd);
    int i = 1;
    while (~scanf("%s", word[i]))
        i++;
    n = i - 1;
    for (int i = 1; i <= n; i++)
        word_len[i] = strlen(word[i]);
    sum[0] = 0;
    for (int i = 1; i <= n; i++)
        sum[i] = sum[i - 1] + word_len[i];
}

int find_end(int s)
{
    int len = word_len[s];
    int i = s + 1;
    while (len + word_len[i] + 1 <= max_len && i <= n)
    {
        len += word_len[i] + 1;
        i++;
    }
    return i;
}

int space_num(int s, int e)
{
    return max_len - (sum[e - 1] - sum[s - 1]);
}

void left(int s, int e)
{
    for (int i = s; i < e - 1; i++)
        printf("%s ", word[i]);
    puts(word[e - 1]);
}

void right(int s, int e)
{
    int num = space_num(s, e);
    for (int i = 0; i < num - (e - s - 1); i++)
        putchar(' ');
    left(s, e);
}

void justify(int s, int e)
{
    if (e - s == 1)
    {
        puts(word[s]);
        return;
    }
    if (e == n + 1)
    {
        left(s, e);
        return;
    }
    int num = space_num(s, e);
    int base = num / (e - s - 1);
    int extra = num % (e - s - 1);
    printf("%s", word[s]);
    for (int i = 1; i <= e - s - 1; i++)
    {
        for (int j = 0; j < base; j++)
            putchar(' ');
        if (i <= extra)
            putchar(' ');
        printf("%s", word[s + i]);
    }
    putchar('\n');
}

void center(int s, int e)
{
    int num = space_num(s, e);
    int temp = num - (e - s - 1);
    int left_space = temp / 2;
    for (int i = 0; i < left_space; i++)
        putchar(' ');
    left(s, e);
}

void work()
{
    int s, e;
    e = s = 1;
    while (e <= n)
    {
        e = find_end(s);
        if (cmd[0] == 'J')
            justify(s, e);
        else if (cmd[0] == 'L')
            left(s, e);
        else if (cmd[0] == 'R')
            right(s, e);
        else
            center(s, e);
        s = e;
    }
}

int main()
{
    //freopen("t.txt", "r", stdin);
    input();
    work();
    return 0;
}