Create Fibonacci in O(log(n)).cpp

Fibonacci in O(log(n)).cpp

@@ -0,0 +1,53 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+typedef long long ll;
+typedef vector< vector<ll> > Matrix;
+const int N = 2;
+const ll mod = 1e9 + 7;
+const Matrix mfib = {{1, 1}, {1, 0}};
+const Matrix midn = {{1, 0}, {0, 1}};
+
+ll gcd(ll a, ll b) {return !a ? b : gcd(b%a, a);}
+ll lcm(ll a, ll b) {return (a*b)/gcd(a, b);}
+
+unordered_map<ll, ll> memo;
+
+inline Matrix mult(const Matrix& a, const Matrix& b, ll MOD = mod) {
+	Matrix ans = {{0, 0}, {0, 0}};
+	for(int i = 0; i < N; i++) {
+		for(int j = 0; j < N; j++) {
+			ll sum = 0;
+			for(int k = 0; k < N; k++) {
+				sum += a[i][k]*b[k][j] % MOD;
+			}
+			ans[i][j] = sum;
+		}
+	}
+	return ans;
+}
+
+inline ll fib(ll n) {
+	if(memo.count(n)) return memo[n];
+	Matrix ans = midn, aux = mfib;
+	for(ll e = n; e; e >>= 1) {
+		if(e & 1) {
+			ans = mult(ans, aux);
+		}
+		aux = mult(aux, aux);
+	}
+	if(n) memo[n-1] = ans[1][1];
+	memo[n+1] = ans[0][0];
+	return memo[n] = ans[0][1];
+}
+
+int main() {
+	ios::sync_with_stdio(0), cin.tie(0);
+	ll n;
+	for(int TC = 1; cin >> n; TC++) {
+		printf("Case: %d\n", TC);
+		printf("fib(%lld) = %lld\n\n", n, fib(n));
+	}
+	return 0;
+}

Reverse each word.c

@@ -0,0 +1,26 @@
+#include <stdio.h>
+#define swap(a, b) ((&(a) == &(b)) ? (a) : (a) ^= (b), (b) ^= (a), (a) ^= (b))
+
+int main() {
+	int l, r, i;
+	char *str;
+	while(~scanf("%m[^\n]", &str)) {
+		for(l = r = i = 0; ; i++) {
+			if(str[i] == '\0') {
+				r = i - 1;
+				while(l < r) {
+					swap(str[l], str[r]);
+					l++, r--;
+				}
+				return 0 * puts(str);
+			} else if(str[i] == ' ') {
+				r = i - 1;
+				while(l < r) {
+					swap(str[l], str[r]);
+					l++, r--;
+				}
+				l = i + 1;
+			}
+		}
+	}
+}