use vstd::prelude::*; fn main() {} verus!{ fn f1_cube_element(nums: &Vec) -> (cubed: Vec) requires forall|k: int| 0 <= k < nums.len() ==> (i32::MIN <= #[trigger] nums[k] * #[trigger] nums[k] <= i32::MAX), forall|k: int| 0 <= k < nums.len() ==> (i32::MIN <= #[trigger] nums[k] * #[trigger] nums[k] * #[trigger] nums[k] <= i32::MAX), { let mut cubed_array: Vec = Vec::new(); let mut i = 0; while i < nums.len() { cubed_array.push(nums[i] * nums[i] * nums[i]); i += 1; } cubed_array } fn f2_is_greater(arr: &Vec, number: i32) -> (result: bool) { let mut i = 0; while i < arr.len() { if number <= arr[i] { return false; } i += 1; } true } spec fn step1(__hp0: Seq, outp: Seq) -> bool { (forall|i: int| 0 <= i < __hp0.len() ==> outp[i] == #[trigger] __hp0[i] * #[trigger] __hp0[i] * #[trigger] __hp0[i]) } spec fn step2(inp: Seq, p2_number: i32, outp: bool) -> bool { (outp == (forall|i: int| 0 <= i < inp.len() ==> p2_number > inp[i])) } fn chain_driver(nums: &Vec, p2_number: i32) -> (r_final: bool) requires forall|k: int| 0 <= k < nums.len() ==> (i32::MIN <= #[trigger] nums[k] * #[trigger] nums[k] <= i32::MAX), forall|k: int| 0 <= k < nums.len() ==> (i32::MIN <= #[trigger] nums[k] * #[trigger] nums[k] * #[trigger] nums[k] <= i32::MAX), ensures exists|v1: Seq| #[trigger] step1(nums@, v1) && step2(v1, p2_number, r_final), { let x1 = f1_cube_element(nums); let x2 = f2_is_greater(&x1, p2_number); proof { assert(step1(nums@, x1@)); assert(step2(x1@, p2_number, x2)); } x2 } } // verus!