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Math 170E HW 2 Question 6
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| /** | |
| * First, compile the program using clang or gcc | |
| * Then, run the program using: ./hw2_better <value of N> <number of runs> <print? T/F=1/0> | |
| * Output is in the file 'out.data', with each run on its own line | |
| * --- | |
| * Example run: ./hw2_better 20 1 1 will run the program once with N=20, printing out the | |
| * contents of the handshake array (how many times each pair of students shook hands) | |
| * | |
| * Example output: | |
| * 0 1 2 3 4 | |
| * ------------------------------ | |
| * 0 1 4 5 6 | |
| * 1 4 5 5 | |
| * 2 5 5 | |
| * 3 7 | |
| * | |
| * It took 47 handshakes for all students to shake hands. | |
| * Students 3 and 4 shook hands the most times, at 7 handshakes. | |
| **/ | |
| #include <time.h> | |
| #include <stdlib.h> | |
| #include <stdio.h> | |
| #define DEFAULT_N 20 | |
| #define DEFAULT_RUNS 100 | |
| int allShookHands(unsigned int** const handshakeArray, int classSize) { | |
| for(unsigned int i = 0; i < classSize - 1; i++) { | |
| for(unsigned int j = i + 1; j < classSize; j++) { | |
| if (handshakeArray[i][j] == 0) | |
| return 0; | |
| } | |
| } | |
| return 1; | |
| } | |
| long long run(int n, int print) { | |
| // Data structures | |
| long long numHandshakes = 0; | |
| unsigned int** handshakeArray = (unsigned int**) calloc(n - 1, sizeof(unsigned int*)); | |
| for (unsigned int i = 0; i < n - 1; i++) { | |
| handshakeArray[i] = (unsigned int*) calloc(n, sizeof(unsigned int)); | |
| } | |
| while(!allShookHands(handshakeArray, n)) { | |
| // Random pair of students | |
| int studentA = 0, studentB = 0; | |
| while(studentA == studentB) { // Should not shake hands with self | |
| studentA = rand() % n; | |
| studentB = rand() % n; | |
| } | |
| // Ensure studentB > studentA | |
| if (studentB < studentA) { | |
| int temp = studentA; | |
| studentA = studentB; | |
| studentB = temp; | |
| } | |
| // Record handshakes | |
| handshakeArray[studentA][studentB] += 1; | |
| // Increase hadnshake count | |
| numHandshakes++; | |
| } | |
| if (print) { | |
| // Table header | |
| printf("\t"); | |
| for (unsigned int i = 0; i < n; i++) { | |
| printf("%6d", i); | |
| } | |
| printf("\n\t"); | |
| for (unsigned int i = 0; i < (6 * n); i++) { | |
| printf("-"); | |
| } | |
| printf("\n"); | |
| // Table contents | |
| unsigned int maxHandshakes = 0; | |
| unsigned int maxPair[2] = {0}; | |
| for (unsigned int i = 0; i < n - 1; i++) { | |
| printf("%d\t", i); | |
| for (unsigned int j = 0; j < n; j++) { | |
| if (j <= i) { | |
| printf("%s", " "); | |
| continue; | |
| } | |
| printf("%6d", handshakeArray[i][j]); | |
| // Set max | |
| if (handshakeArray[i][j] > maxHandshakes) { | |
| maxHandshakes = handshakeArray[i][j]; | |
| maxPair[0] = i; | |
| maxPair[1] = j; | |
| } | |
| } | |
| printf("\n"); | |
| } | |
| // Summary | |
| printf("\n"); | |
| printf("It took %lld handshakes for all students to shake hands.\n", numHandshakes); | |
| printf("Students %d and %d shook hands the most times, at %d handshakes.\n", maxPair[0], maxPair[1], maxHandshakes); | |
| } | |
| // Ending stuff | |
| for (int i = 0; i < n - 1; i++) { | |
| free(handshakeArray[i]); | |
| } | |
| free(handshakeArray); | |
| return numHandshakes; | |
| } | |
| int main(int argc, char** argv) { | |
| // Initialize random function | |
| srand(time(NULL)); | |
| // Take in CLI args | |
| // First: # for N | |
| // Second: # of runs | |
| // Third: print handshake array? T/F | |
| int n = DEFAULT_N; | |
| int runs = DEFAULT_RUNS; | |
| int print = 0; | |
| if (argc >= 3) { | |
| sscanf(argv[1], "%d", &n); | |
| sscanf(argv[2], "%d", &runs); | |
| } | |
| if (argc == 4) { | |
| sscanf(argv[3], "%d", &print); | |
| } | |
| // Store results | |
| long long* results = (long long*) calloc(runs, sizeof(long long)); | |
| for (int i = 0; i < runs; i++) { | |
| results[i] = run(n, print); | |
| } | |
| // Write results | |
| FILE *f = fopen("out.data", "wb"); | |
| for (int i = 0; i < runs; i++) { | |
| fprintf(f, "%lld\n", results[i]); | |
| } | |
| fclose(f); | |
| // Ending stuff | |
| free(results); | |
| return 0; | |
| } |
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| #include <time.h> | |
| #include <stdlib.h> | |
| #include <stdio.h> | |
| #define N 20 | |
| #define RUNS 100 | |
| int allShookHands(const int handshakeArray[N][N], int classSize) { | |
| for(int i = 0; i < classSize; i++) { | |
| for(int j = 0; j < classSize; j++) { | |
| if (handshakeArray[i][j] == 0) | |
| return 0; | |
| } | |
| } | |
| return 1; | |
| } | |
| long long run() { | |
| // Data structures | |
| long long numHandshakes = 0; | |
| int handshakeArray[N][N] = {0}; | |
| while(!allShookHands(handshakeArray, N)) { | |
| // Random pair of students | |
| int studentA = rand() % N; | |
| int studentB = rand() % N; | |
| // Record handshakes | |
| handshakeArray[studentA][studentB] = 1; | |
| // Increase hadnshake count | |
| numHandshakes++; | |
| } | |
| return numHandshakes; | |
| } | |
| void main(int argc, int** argv) { | |
| // Initialize random function | |
| srand(time(NULL)); | |
| // Store results | |
| long long results[RUNS] = {0}; | |
| for (int i = 0; i < RUNS; i++) { | |
| results[i] = run(); | |
| } | |
| // Write results | |
| FILE *f = fopen("out.data", "wb"); | |
| for (int i = 0; i < RUNS; i++) { | |
| fprintf(f, "%lld\n", results[i]); | |
| } | |
| fclose(f); | |
| } |
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