Solved 19

Co-authored-by: sigonasr2 <sigonasr2@gmail.com>

archives/19/src/main.c

@@ -0,0 +1,89 @@
+#include <stdio.h>
+#include "utils.h"
+
+/*
+    You are given the following information, but you may prefer to do some research for yourself.
+
+    1 Jan 1900 was a Monday.
+    Thirty days has September,
+    April, June and November.
+    All the rest have thirty-one,
+    Saving February alone,
+    Which has twenty-eight, rain or shine.
+    And on leap years, twenty-nine.
+    A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
+    How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
+
+    https://projecteuler.net/problem=19
+*/
+
+enum Month {JANUARY=1,FEBRUARY,MARCH,APRIL,MAY,JUNE,JULY,AUGUST,SEPTEMBER,OCTOBER,NOVEMBER,DECEMBER};
+
+int DaysInMonth(enum Month month,int year) {
+    switch (month) {
+        case JANUARY:
+        case MARCH:
+        case MAY:
+        case JULY:
+        case AUGUST:
+        case OCTOBER:
+        case DECEMBER:{
+            return 31;
+        }break;
+        case APRIL:
+        case JUNE:
+        case SEPTEMBER:
+        case NOVEMBER:{
+            return 30;
+        }break;
+        case FEBRUARY:{
+            return ((year%100==0)&&(year%400!=0))?28:(year%4==0)?29:28;
+        }break;
+    }
+}
+
+int main(int argc,char**argv) {
+    int day=1;
+    enum Month month=1;
+    int year=1900;
+    enum Weekday{
+        SUNDAY,
+        MONDAY,
+        TUESDAY,
+        WEDNESDAY,
+        THURSDAY,
+        FRIDAY,
+        SATURDAY,
+    } weekday=MONDAY;
+
+    int sundayCount=0;
+
+    while((day!=31)||(month!=12)||(year!=2000)) {
+        printf("Date: %d/%d/%d\n",month,day,year);
+        if (year>=1901) {
+            //Start counting Sundays.
+            if (weekday==SUNDAY&&day==1) {
+                sundayCount++;
+            }
+        }
+        //Increment the day.
+        if (day+1<=DaysInMonth(month,year)) {
+            day++;
+        } else 
+        if (month+1<=12){
+            //It's a new month.
+            month++;
+            day=1;
+        } else {
+            //It's a new year!
+            year++;
+            day=1;
+            month=1;
+            //printf("The year is now %d...\n",year);
+        }
+        weekday=((weekday+1)<=SATURDAY)?weekday+1:SUNDAY;
+    }
+
+    printf("\n\n%d Sundays were on the 1st of the month.",sundayCount);
+    return 0;
+}

archives/19/src/utils.c

@@ -0,0 +1,72 @@
+#include "utils.h"
+#include <stdio.h>
+#include <stdlib.h>
+
+struct String add(struct String numb1, struct String numb2){
+    byte carryover=0;
+    int digitCount=0;
+    char*str = malloc(0);
+    if (numb1.length>=numb2.length) {
+        for (int offset=0;offset<numb1.length;offset++) {
+            str = realloc(str,++digitCount);
+            //printf("Digit count is now %d\n",digitCount);
+            if (numb2.length>offset) {
+                //printf("%c %c\n",numb1.str[numb1.length-offset-1],numb2.str[numb2.length-offset-1]);
+                int sum=((numb1.str[numb1.length-offset-1]-'0')+(numb2.str[numb2.length-offset-1]-'0'))+((carryover>0)?carryover--:0);
+                if (sum>=10) {
+                    carryover=1;
+                    sum-=10;
+                }
+                str[offset]=sum+'0';
+            } else {
+                str[offset]=numb1.str[numb1.length-offset-1];
+            }
+        }
+    } else {
+        for (int offset=0;offset<numb2.length;offset++) {
+            str = realloc(str,++digitCount);
+            //printf("Digit count is now %d\n",digitCount);
+            if (numb1.length>offset) {
+                //printf("%c %c\n",numb1.str[numb1.length-offset-1],numb2.str[numb2.length-offset-1]);
+                int sum=((numb1.str[numb1.length-offset-1]-'0')+(numb2.str[numb2.length-offset-1]-'0'))+((carryover>0)?carryover--:0);
+                if (sum>=10) {
+                    carryover=1;
+                    sum-=10;
+                }
+                str[offset]=sum+'0';
+            } else {
+                str[offset]=numb2.str[numb2.length-offset-1];
+            }
+        }
+    }
+    if (carryover>0) {
+        str = realloc(str,++digitCount);
+        str[digitCount-1]='1';
+    }
+    for (int i=0;i<digitCount/2;i++) {
+        char c = str[i];
+        char c2 = str[digitCount-i-1];
+        str[digitCount-i-1]=c;
+        str[i]=c2;
+    }
+    struct String newStr = {digitCount,str};
+    return newStr;
+}
+
+void printLongDoubleArr(int a,int b,long doubleArr[a][b]) {
+    for (int i=0;i<a;i++) {
+        for (int j=0;j<b;j++) {
+            printf("%ld\t",doubleArr[i][j]);
+        }
+        printf("\n");
+    }
+}
+
+void printIntDoubleArr(int a,int b,int doubleArr[a][b]) {
+    for (int i=0;i<a;i++) {
+        for (int j=0;j<b;j++) {
+            printf("%d\t",doubleArr[i][j]);
+        }
+        printf("\n");
+    }
+}

archives/19/src/utils.h

@@ -0,0 +1,11 @@
+#define true 1
+#define false 0
+#define boolean char
+#define byte char
+struct String{
+    int length;
+    char*str;
+};
+struct String add(struct String numb1, struct String numb2);
+void printLongDoubleArr(int a,int b,long doubleArr[a][b]);
+void printIntDoubleArr(int a,int b,int doubleArr[a][b]);

src/main.c

@@ -2,13 +2,88 @@
 #include "utils.h"
 
 /*
-    
+    You are given the following information, but you may prefer to do some research for yourself.
 
-    https://projecteuler.net/problem=
+    1 Jan 1900 was a Monday.
+    Thirty days has September,
+    April, June and November.
+    All the rest have thirty-one,
+    Saving February alone,
+    Which has twenty-eight, rain or shine.
+    And on leap years, twenty-nine.
+    A leap year occurs on any year evenly divisible by 4, but not on a century unless it is divisible by 400.
+    How many Sundays fell on the first of the month during the twentieth century (1 Jan 1901 to 31 Dec 2000)?
+
+    https://projecteuler.net/problem=19
 */
 
+enum Month {JANUARY=1,FEBRUARY,MARCH,APRIL,MAY,JUNE,JULY,AUGUST,SEPTEMBER,OCTOBER,NOVEMBER,DECEMBER};
+
+int DaysInMonth(enum Month month,int year) {
+    switch (month) {
+        case JANUARY:
+        case MARCH:
+        case MAY:
+        case JULY:
+        case AUGUST:
+        case OCTOBER:
+        case DECEMBER:{
+            return 31;
+        }break;
+        case APRIL:
+        case JUNE:
+        case SEPTEMBER:
+        case NOVEMBER:{
+            return 30;
+        }break;
+        case FEBRUARY:{
+            return ((year%100==0)&&(year%400!=0))?28:(year%4==0)?29:28;
+        }break;
+    }
+}
+
 int main(int argc,char**argv) {
-    int testArr[][5] = {{1,2,3,4},{1,2,5,3},{6,2,1,7},{2,3,1,631},{1,0,0,0,1}};
+    int day=1;
-    printIntDoubleArr(5,5,testArr);
+    enum Month month=1;
+    int year=1900;
+    enum Weekday{
+        SUNDAY,
+        MONDAY,
+        TUESDAY,
+        WEDNESDAY,
+        THURSDAY,
+        FRIDAY,
+        SATURDAY,
+    } weekday=MONDAY;
+
+    int sundayCount=0;
+
+    while((day!=31)||(month!=12)||(year!=2000)) {
+        printf("Date: %d/%d/%d\n",month,day,year);
+        if (year>=1901) {
+            //Start counting Sundays.
+            if (weekday==SUNDAY&&day==1) {
+                sundayCount++;
+            }
+        }
+        //Increment the day.
+        if (day+1<=DaysInMonth(month,year)) {
+            day++;
+        } else 
+        if (month+1<=12){
+            //It's a new month.
+            month++;
+            day=1;
+        } else {
+            //It's a new year!
+            year++;
+            day=1;
+            month=1;
+            //printf("The year is now %d...\n",year);
+        }
+        weekday=((weekday+1)<=SATURDAY)?weekday+1:SUNDAY;
+    }
+
+    printf("\n\n%d Sundays were on the 1st of the month.",sundayCount);
     return 0;
 }