算法刷题记录(Day 77)

原题链接

题目类型:动态规划

#include
#include
#include
#include
using namespace std;
int n;
#define NMAX 1000006
int num[NMAX];
vector dp;
long long res;
int main() {
	cin >> n;
	memset(&res, 0xff, sizeof(res));
	for (int i = 0; i < n; i++) cin >> num[i];
	dp.push_back(num[0]);
	for (int i = 1; i < n; i++) {
		long long cur = max((long long)num[i], num[i] + dp[i - 1]);
		dp.push_back(cur);
		res = max(res, cur);
	}
	cout << res << endl;
}

题目类型:动态规划

#include
#include
#include
#include
using namespace std;
int n;
#define NMAX 1003
long long dp[NMAX];
int main() {
	cin >> n;
	memset(dp, 0, sizeof(dp));
	dp[1] = 1;
	dp[0] = 1;
	for (int i = 2; i <= n; i++) {
		for (int j = 0; j <= i-1; j++) {
			dp[i] += dp[j] * dp[i-1 - j];
		}
	}
	cout << dp[n] << endl;
}

题目类型:模拟

#include
#include
#include
#include
using namespace std;
int n;
#define NMAX 1003
typedef long long LL;
LL var[2], val[2];
int pos;
char c;
int symbol = 1, num = 0, is = 0;
int main() {
	memset(var, 0, sizeof(var));
	memset(val, 0, sizeof(val));
	pos = 0;
	while ((c = getchar()) != 'n') {
		if (c == 'x') {
			is = 1;
			if (num == 0) num = 1;//注意处理只有x时前面没有数字的情况 
		}
		else if (c == '-' || c=='+' || c=='=') {
			if (is) var[pos] += num * symbol;
			else val[pos] += num * symbol;
			if (c == '-') symbol = -1;
			else symbol = 1;
			num = 0;
			is = 0;
			if (c == '=') {
				pos = 1;
			}
		}
		else {
			num = num * 10 + c - '0';
		}
	}
	//最后的调试
	if (is) var[pos] += num * symbol;
	else val[pos] += num * symbol;
	long long rvar = var[0] - var[1];
	long long rval = val[1] - val[0];
	if (rvar == rval && rvar == 0) cout << "infinite solutions" << endl;
	else if (rvar == 0 && rvar != 0) cout << "no solution" << endl;
	else cout << "x=" << rval / rvar << endl;
}