AOJ/堆与动态规划习题集

ALDS1_9_A-CompleteBinaryTree.

Codes:

//#define LOCAL

#include <cstdio>

int parent(int i) { return i/2; }
int left(int i) { return i*2; }
int right(int i) { return i*2+1; }

int main()
{
	#ifdef LOCAL
		freopen("E:\Temp\input.txt", "r", stdin);
		freopen("E:\Temp\output.txt", "w", stdout);
	#endif

	int i, n, A[300];
	scanf("%d", &n);
	for(i=1; i<=n; ++i) scanf("%d", &A[i]);
	
	for(i=1; i<=n; ++i) {
		printf("node %d: key = %d, ", i, A[i]);
		if(parent(i) >= 1) printf("parent key = %d, ", A[i/2]);
		if(left(i) <= n) printf("left key = %d, ", A[i*2]);
		if(right(i) <= n) printf("right key = %d, ", A[i*2+1]);
		printf("
");
	}

	return 0;
}

ALDS1_9_B-MaximumHeap.

Codes:

//#define LOCAL

#include <cstdio>

int i, n, A[500010];

void swap(int &a, int &b) {
	int t = a;
	a = b; b = t;
}

void maxHeapify(int a) {
	int l = a*2, r = a*2+1, maxn;
	if(l<=n && A[l]>A[a]) maxn = l;
	else maxn = a;
	if(r<=n && A[r]>A[maxn]) maxn = r;
	if(maxn != a) {
		swap(A[maxn], A[a]);
		maxHeapify(maxn);
	}
}

int main()
{
	#ifdef LOCAL
		freopen("E:\Temp\input.txt", "r", stdin);
		freopen("E:\Temp\output.txt", "w", stdout);
	#endif

	scanf("%d", &n);
	for(i=1; i<=n; ++i) scanf("%d", &A[i]); 

	for(i=n/2; i>=1; --i) maxHeapify(i);
	for(i=1; i<=n; ++i) printf(" %d", A[i]);
	printf("
");

	return 0;
}

ALDS1_9_C-PriorityQueue.

Codes:

//#define LOCAL

#include <cstdio>

#define M 2000000
#define I (1<<30)
int i, n, A[M];

void swap(int &a, int &b) {
	int t = a;
	a = b; b = t;
}

void maxHeapify(int a) {
	int l = a*2, r = a*2+1, maxn;
	if(l<=n && A[l]>A[a]) maxn = l;
	else maxn = a;
	if(r<=n && A[r]>A[maxn]) maxn = r;
	if(maxn != a) {
		swap(A[maxn], A[a]);
		maxHeapify(maxn);
	}
}

int extract() {
	int maxv;
	if(n < 1) return -I;
	maxv = A[1]; A[1] = A[n--];
	maxHeapify(1);
	return maxv;
}

void increaseKey(int i, int key) {
	if(key < A[i]) return;
	A[i] = key;
	while(i>1 && A[i/2]<A[i]) {
		swap(A[i], A[i/2]);
		i /= 2;
	}
}

void insert(int key) {
	++n;
	A[n] = -I;
	increaseKey(n, key);
}

int main()
{
	#ifdef LOCAL
		freopen("E:\Temp\input.txt", "r", stdin);
		freopen("E:\Temp\output.txt", "w", stdout);
	#endif

	int key;
	char com[10];

	while(1) {
		scanf("%s", com);
		if(com[0]=='e' && com[1]=='n') break;
		if(com[0] == 'i') {
			scanf("%d", &key);
			insert(key);
		} else printf("%d
", extract());
	}

	return 0;
}

ALDS1_10_A-FibonacciNumber.

Codes:

//#define LOCAL

#include <cstdio>

int main()
{
	#ifdef LOCAL
		freopen("E:\Temp\input.txt", "r", stdin);
		freopen("E:\Temp\output.txt", "w", stdout);
	#endif

	int i, n, F[50];
	F[0] = 1, F[1] = 1;
	scanf("%d", &n);
	for(i=2; i<=n; ++i)
		F[i] = F[i-1]+F[i-2];
	printf("%d
", F[n]);

	return 0;
}

ALDS1_10_C-LongestCommonSubsequence.

Codes: