题解 | #矩阵乘法计算量估算#
矩阵乘法计算量估算
http://www.nowcoder.com/practice/15e41630514445719a942e004edc0a5b
const length = parseInt( readline() )
const arr = []
for( let i = 0; i < length; i ++ ) {
const itemArr = readline().split(" ")
arr.push(itemArr)
}
const str = readline()
const numberArr = []
const todoArr = []
let sum = 0;
function mul( arr1, arr2 ) {
const [ x, xy ] = arr1
const [ yy, z ] = arr2
const currentSum = x * xy * z
sum += currentSum
return [ x, z ]
}
function calc() {
const right = numberArr.pop()
const left = numberArr.pop()
const current = mul( left, right )
numberArr.push(current)
todoArr.pop()
}
for( let i = 0, l = str.length; i < l; i++ ) {
if( str[i] === "(" ) {
todoArr.push("(")
}else if( str[i] === ")" ) {
calc()
}else {
numberArr.push( arr.shift() )
}
}
while( todoArr.length ) {
calc()
}
console.log( sum )
