洛谷1415 拆分数列

原题链接

太菜了，又去看了题解（\(DP\)写一道看一道\(QAQ\)
题解

#include<cstdio>
using namespace std;
const int N = 510;
int a[N], f[N], g[N], l;
inline void re_l()
{
	char c = getchar();
	l = 0;
	for (; c < '0' || c > '9'; c = getchar());
	for (; c >= '0' && c <= '9'; c = getchar())
		a[++l] = c - '0';
}
inline int maxn(int x, int y)
{
	return x > y ? x : y;
}
bool cmp(int x, int y, int xx, int yy)
{
	for (; !a[x] && x <= y; x++);
	for (; !a[xx] && xx <= yy; xx++);
	int z = y - x + 1, zz = yy - xx + 1;
	if (!z || !zz || z < zz)
		return false;
	if (z > zz)
		return true;
	for (; x <= y; x++, xx++)
	{
		if (a[x] > a[xx])
			return true;
		else
			if (a[x] < a[xx])
				return false;
	}
	return false;
}
int main()
{
	int i, j, nw = 1;
	bool p = 0;
	re_l();
	for (i = 1; i <= l; i++)
	{
		for (j = i; j; j--)
			if (cmp(j, i, f[j - 1], j - 1))
				break;
		f[i] = maxn(1, j);
	}
	g[f[l]] = l;
	for (i = f[l]; !a[i - 1]; g[--i] = l);
	for (i = f[l] - 1; i; i--)
	{
		for (j = f[l] - 1; j >= i; j--)
			if (cmp(j + 1, g[j + 1], i, j))
				break;
		g[i] = maxn(maxn(g[i], i), j);
	}
	for (; nw <= l; nw = g[nw] + 1)
	{
		if (p)
			putchar(',');
		p = 1;
		for (i = nw; i <= g[nw]; i++)
			printf("%d", a[i]);
	}
	return 0;
}