DP HDOJ 5471 Count the Grid

#include 
using namespace std;
typedef long long LL;

#define mp(x, y) make_pair(x, y)
const int maxn = 100;
const int mod = 1e9+7;

struct line
{
	int x1, y1, x2, y2, v;
	line() {}
	line(int x1, int y1, int x2, int y2, int v) : x1(x1), y1(y1), x2(x2), y2(y2), v(v) {}
}l[maxn];

LL dp[2][1  > vec;
int N, n, m;

int solve(int xx, int yy, int pos1, int pos2)
{
	vec.clear();
	for(int i = 1; i = l[i].x1 && xx = l[i].y1 && yy