pr-meltout

level1/p01_runningLetter/runningLetter.c

@@ -0,0 +1,38 @@
+#include <stdio.h>
+#include <windows.h>
+#include <string.h>
+
+#define MAXN 100
+#define EDGE 120
+#define SPEED 10
+
+void PrintStr(char s[], int x, int y)
+{
+	HANDLE hd;
+	COORD pos;
+	pos.X = x;
+	pos.Y = y;
+	hd = GetStdHandle(STD_OUTPUT_HANDLE);
+	SetConsoleCursorPosition(hd, pos);
+	printf("%s",s);
+}
+
+int main()
+{
+	char a[MAXN]="a";
+	int x = 1, y = 0, dir = 1, len = strlen(a);
+	PrintStr(a, 0, 0); Sleep(50);
+	while (1)
+	{
+		system("cls");
+		if (x == 0 || x == EDGE - len)
+		{
+			dir *= -1;
+			y++;
+		}
+		x += dir;
+		PrintStr(a, x, y);
+		Sleep(SPEED);
+	}
+	return 0;
+}

level1/p02_isPrime/isPrime.c

@@ -0,0 +1,24 @@
+#include <stdio.h>
+#include <math.h>
+
+typedef long long ll;
+
+int isPrime(ll x)
+{
+    if(x==1)return 0;
+	ll sq = sqrt(x);
+	for (int i = 2; i <= sq; ++i)
+	{
+		if (x%i == 0)return 0;
+	}
+	return 1;
+}
+
+int main()
+{
+	ll num;
+	scanf("%I64d",&num);
+	if (isPrime(num))printf("a prime\n");
+	else printf("not a prime\n");
+	return 0;
+}

level1/p03_Diophantus/Diophantus.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include <math.h>
+
+int main()
+{
+	for (int age = 0; age <= 200; ++age)
+	{
+		if (age % 12 == 0 && age % 7 == 0 && age - age / 6 - age / 12 - age / 7 - 5 - 4 == age / 2)
+		{
+			printf("age = %d\n", age - 4);
+			break;
+		}
+	}
+	return 0;
+}

level1/p04_ narcissus/narcissus.c

@@ -0,0 +1,16 @@
+#include <stdio.h>
+#include <math.h>
+
+int main()
+{
+	int x, y, z;
+	for (int i = 100; i < 1000; ++i)
+	{
+		x = i / 100;
+		y = (i - i / 100 * 100) / 10;
+		z = i % 10;
+		if (pow(x, 3) + pow(y, 3) + pow(z, 3) == i)
+			printf("%d\n", i);
+	}
+	return 0;
+}

level1/p05_allPrimes/allPrimes.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <time.h>
+#define MAXN 1000
+
+int notprime[MAXN + 5], primes[MAXN + 5], len;
+
+void GetPrime()
+{
+	for (int i = 2; i <= MAXN; i++)
+	{
+		if (!notprime[i])
+		{
+			primes[len++] = i;
+			printf("%d\n", i);
+		}
+		for (int j = 0; j < len; j++)
+		{
+			if (i*primes[j] > MAXN) break;
+			notprime[i*primes[j]] = 1;
+			if (i%primes[j] == 0) break;
+		}
+	}
+}
+
+int main()
+{
+	clock_t StartTime, FinishTime;
+	StartTime = clock();
+	GetPrime();
+	FinishTime = clock();
+	printf("%.3lf seconds", (double)(FinishTime - StartTime) / CLOCKS_PER_SEC);
+	//system("pause");
+	return 0;
+}

level1/p06_Goldbach/Goldbach.c

@@ -0,0 +1,46 @@
+#include <stdio.h>
+#include <time.h>
+#include <string.h>
+
+#define MAXN 100
+
+int isprime[MAXN + 5], primes[MAXN + 5], len;
+
+void GetPrime()
+{
+	memset(isprime, 1, sizeof(isprime));
+	isprime[0] = isprime[1] = 0;
+	for (int i = 2; i <= MAXN; i++)
+	{
+		if (isprime[i])primes[len++] = i;
+		for (int j = 0; j < len; j++)
+		{
+			if (i*primes[j] > MAXN) break;
+			isprime[i*primes[j]] = 0;
+			if (i%primes[j] == 0) break;
+		}
+	}
+}
+
+int main()
+{
+	GetPrime();
+	int flag;
+	for (int i = 4; i <= 100; i += 2)
+	{
+		flag = 0;
+		for (int j = 0; j < len; ++j)
+		{
+			if (isprime[i - primes[j]])
+				flag = 1;
+		}
+		if (!flag)
+		{
+			printf("false\n");
+			return 0;
+		}
+	}
+	printf("true\n");
+	//system("pause");
+	return 0;
+}

level1/p07_encrypt_decrypt/encrypt_decrypt(rsa&xor).c

@@ -0,0 +1,130 @@
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define MINN 1000
+#define MAXN 10000
+
+typedef long long ll;
+
+ll n, p, q, e, d, x, y, phi, iv, cipher[MAXN];
+ll len, MesLen, primes[MAXN + 5], isprime[MAXN + 5];
+char Message[MAXN], DecMes[MAXN];
+
+int GetRand(int LowerBound, int UpperBound)
+{
+	return rand() % (UpperBound - LowerBound + 1) + LowerBound;
+}
+
+void GetPrime()
+{
+	memset(isprime, 1, sizeof(isprime));
+	isprime[0] = isprime[1] = 0;
+	for (int i = 2; i <= MAXN; i++)
+	{
+		if (isprime[i])primes[len++] = i;
+		for (int j = 0; j < len; j++)
+		{
+			if (i*primes[j] > MAXN) break;
+			isprime[i*primes[j]] = 0;
+			if (i%primes[j] == 0) break;
+		}
+	}
+}
+
+ll gcd(ll a, ll b)
+{
+	if (b == 0)return a;
+	return gcd(b, a%b);
+}
+
+ll pow_mod(ll a, ll b, ll mod)
+{
+	ll ans = 1;
+	while (b)
+	{
+		if (b & 1)ans = ans * a%mod;
+		a = a * a%mod; b >>= 1;
+	}
+	return ans;
+}
+
+ll exgcd(ll a, ll b)
+{
+	ll d = a, tmp;
+	if (b != 0)
+	{
+		tmp = x; x = y; y = tmp;
+		d = exgcd(b, a % b);
+		tmp = x; x = y; y = tmp;
+		y -= (a / b) * x;
+	}
+	else
+	{
+		x = 1; y = 0;
+	}
+	return d;
+}
+
+ll mod_inverse(ll a, ll mod)
+{
+	exgcd(a, mod);
+	return (mod + x % mod) % mod;
+}
+
+void init()
+{
+	srand(time(NULL));
+	iv = GetRand(0, 255);
+	GetPrime();
+	p = primes[GetRand(1000, len - 1)];
+	q = primes[GetRand(1000, len - 1)];
+	n = p * q;
+	phi = (p - 1)*(q - 1);
+	e = GetRand(10, phi - 1);
+	while (gcd(e, phi) != 1)
+		e = GetRand(10, phi - 1);
+	d = mod_inverse(e, phi);
+}
+
+ll RSA_enc(ll x)
+{
+	x = pow_mod(x, e, n);
+	return x;
+}
+
+ll RSA_dec(ll x)
+{
+	return (char)pow_mod(x, d, n);
+}
+
+void get_enc()
+{
+	cipher[0] = iv;
+	for (int i = 1; i <= MesLen; ++i)
+		cipher[i] = RSA_enc(cipher[i - 1] ^ (ll)Message[i - 1]);
+}
+
+void get_dec()
+{
+	cipher[0] = iv;
+	for (int i = 0; i < MesLen; ++i)
+		DecMes[i] = (char)RSA_dec(cipher[i + 1]) ^ cipher[i];
+}
+
+int main()
+{
+	init();
+	scanf("%s", Message);
+	MesLen = strlen(Message);
+	get_enc();
+	printf("cipher is : ");
+	for (int i = 1; i <= MesLen; ++i)
+		printf("%010I64d", cipher[i]);
+	printf("\n");
+	get_dec();
+	printf("Decrypted Message is : %s", DecMes);
+	return 0;
+}

level1/p07_encrypt_decrypt/encrypt_decrypt.c

@@ -0,0 +1,66 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <time.h>
+
+#define MAXN 1000005
+
+int XorArray[MAXN], n;
+char Message[MAXN], Cipher[MAXN * 2], DecMess[MAXN];
+
+char ToHex(int _oct)
+{
+	if (_oct < 10)return _oct + '0';
+	else return _oct - 10 + 'a';
+}
+
+int ToOct(int _hex)
+{
+	if (_hex >= '0' && _hex <= '9')return _hex - '0';
+	else return _hex - 'a' + 10;
+}
+
+int GetRand(int LowerBound, int UpperBound)
+{
+	return rand() % (UpperBound - LowerBound + 1) + LowerBound;
+}
+
+void GenerateXorArray()
+{
+	n = GetRand(10, 100);
+	for (int i = 0; i < n; ++i)
+		XorArray[i] = GetRand(0, 255);
+}
+
+void Encrypt()
+{
+	int num, len = strlen(Message);
+	for (int i = 0; i < len; ++i)
+	{
+		num = (int)Message[i] ^ XorArray[i%n];
+		Cipher[i * 2] = ToHex(num / 16);
+		Cipher[i * 2 + 1] = ToHex(num % 16);
+	}
+}
+
+void Decrypt()
+{
+	int num, len = strlen(Cipher);
+	for (int i = 0; i < len; i += 2)
+	{
+		num = ToOct(Cipher[i]) * 16 + ToOct(Cipher[i + 1]);
+		DecMess[i / 2] = (char)(num^XorArray[(i / 2) % n]);
+	}
+}
+
+int main()
+{
+	srand(time(NULL));
+	GenerateXorArray();
+	scanf("%s", Message);
+	Encrypt();
+	printf("Cipher = %s\n", Cipher);
+	Decrypt();
+	printf("Decrypted Message = %s\n", DecMess);
+	return 0;
+}