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@ -2,88 +2,23 @@ |
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#include "utils.h" |
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/*
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You are given the following information, but you may prefer to do some research for yourself. |
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n! means n × (n − 1) × ... × 3 × 2 × 1 |
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1 Jan 1900 was a Monday. |
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Thirty days has September, |
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April, June and November. |
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All the rest have thirty-one, |
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Saving February alone, |
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Which has twenty-eight, rain or shine. |
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And on leap years, twenty-nine. |
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A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400. |
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How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)? |
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For example, 10! = 10 × 9 × ... × 3 × 2 × 1 = 3628800, |
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and the sum of the digits in the number 10! is 3 + 6 + 2 + 8 + 8 + 0 + 0 = 27. |
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https://projecteuler.net/problem=19
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*/ |
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enum Month {JANUARY=1,FEBRUARY,MARCH,APRIL,MAY,JUNE,JULY,AUGUST,SEPTEMBER,OCTOBER,NOVEMBER,DECEMBER}; |
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Find the sum of the digits in the number 100! |
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int DaysInMonth(enum Month month,int year) { |
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switch (month) { |
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case JANUARY: |
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case MARCH: |
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case MAY: |
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case JULY: |
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case AUGUST: |
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case OCTOBER: |
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case DECEMBER:{ |
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return 31; |
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}break; |
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case APRIL: |
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case JUNE: |
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case SEPTEMBER: |
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case NOVEMBER:{ |
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return 30; |
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}break; |
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case FEBRUARY:{ |
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return ((year%100==0)&&(year%400!=0))?28:(year%4==0)?29:28; |
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}break; |
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} |
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} |
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https://projecteuler.net/problem=20
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*/ |
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int main(int argc,char**argv) { |
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int day=1; |
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enum Month month=1; |
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int year=1900; |
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enum Weekday{ |
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SUNDAY, |
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MONDAY, |
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TUESDAY, |
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WEDNESDAY, |
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THURSDAY, |
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FRIDAY, |
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SATURDAY, |
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} weekday=MONDAY; |
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int sundayCount=0; |
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while((day!=31)||(month!=12)||(year!=2000)) { |
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printf("Date: %d/%d/%d\n",month,day,year); |
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if (year>=1901) { |
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//Start counting Sundays.
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if (weekday==SUNDAY&&day==1) { |
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sundayCount++; |
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} |
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} |
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//Increment the day.
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if (day+1<=DaysInMonth(month,year)) { |
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day++; |
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} else
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if (month+1<=12){ |
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//It's a new month.
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month++; |
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day=1; |
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} else { |
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//It's a new year!
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year++; |
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day=1; |
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month=1; |
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//printf("The year is now %d...\n",year);
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} |
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weekday=((weekday+1)<=SATURDAY)?weekday+1:SUNDAY; |
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struct String factorialSum = {1,"0"}; |
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int counter=1; |
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mult((struct String){3,"575"},(struct String){4,"4200"}); |
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while (counter<=100) { |
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counter++; |
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} |
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printf("\n\n%d Sundays were on the 1st of the month.",sundayCount); |
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return 0; |
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} |