Problem:
Score : 600 points

Problem Statement

Snuke is standing on a two-dimensional plane. In one operation, he can move by 1 in the positive x-direction, or move by 1 in the positive y-direction.

Let us define a function f(r, c) as follows:

f(r,c) := (The number of paths from the point (0, 0) to the point (r, c) that Snuke can trace by repeating the operation above)

Given are integers r_1, r_2, c_1, and c_2.
Find the sum of f(i, j) over all pair of integers (i, j) such that r_1 ≤ i ≤ r_2 and c_1 ≤ j ≤ c_2, and compute this value modulo (10^9+7).

Constraints

1 ≤ r_1 ≤ r_2 ≤ 10^6

1 ≤ c_1 ≤ c_2 ≤ 10^6

All values in input are integers.

Input

Input is given from Standard Input in the following format:

r_1 c_1 r_2 c_2

Output

Print the sum of f(i, j) modulo (10^9+7).

Sample Input 1

1 1 2 2

Sample Output 1

14

For example, there are two paths from the point (0, 0) to the point (1, 1): (0,0) → (0,1) → (1,1) and (0,0) → (1,0) → (1,1), so f(1,1)=2.

Similarly, f(1,2)=3, f(2,1)=3, and f(2,2)=6. Thus, the sum is 14.

Sample Input 2

314 159 2653 589

Sample Output 2

602215194

Solution in Python (3.4.3) (judge verdict: Wrong Answer)


import numpy as np
import sys
sys.setrecursionlimit(100000)



def acinput():
    return list(map(int, input().split(" ")))



directions=np.array([[1,0],[0,1],[-1,0],[0,-1]])
directions = list(map(np.array, directions))

mod = 10**9+7


def factorial(n):
    fact = 1
    for integer in range(1, n + 1):
        fact *= integer
    return fact



def serch(x, count):
    #print("top", x, count)
            

    for d in directions:
        nx = d+x
        #print(nx)
        if np.all(0 <= nx) and np.all(nx < (H, W)):
            if field[nx[0]][nx[1]] == "E":
                count += 1 
                field[nx[0]][nx[1]] = "V"
                count = serch(nx, count)  
                continue
            if field[nx[0]][nx[1]] == "#":
                field[nx[0]][nx[1]] = "V"
                count = serch(nx, count)    
                 
    return count


def cmb(n, r):
    if n - r < r:
        r = n - r
    if r == 0:
        return 1
    if r == 1:
        return n

    numerator = [n - r + k + 1 for k in range(r)]
    denominator = [k + 1 for k in range(r)]

    for p in range(2, r+1):
        pivot = denominator[p - 1]
        if pivot > 1:
            offset = (n - r) % p
            for k in range(p-1, r, p):
                numerator[k - offset] /= pivot
                denominator[k] /= pivot

    result = 1
    for k in range(r):
        if numerator[k] > 1:
            result *= int(numerator[k])
            #print(result)
            result %= (10**9+7)

    return result

r1,c1,r2,c2=acinput()

print(cmb(c1+r1,r1)-cmb(c1+r2+1,r2+1)-cmb(c2+r1+1,r1)+cmb(c2+r2+2,r2+1))

#r1=1;r2=2;c1=1;c2=2;Sum[Binomial[r+c,r], {r, r1, r2},{c,c1,c2}]